diff --git a/src/array.c b/src/array.c
index f9140eb..3fa7e96 100644
--- a/src/array.c
+++ b/src/array.c
@@ -42,13 +42,13 @@ struct _array {
 array array_init(const int element_count, const size_t data_size)
 {
     struct _array *const init = malloc(sizeof(struct _array));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
     init->element_count = element_count;
     init->data = calloc((size_t) element_count, data_size);
-    if (init->data == NULL) {
+    if (!init->data) {
         free(init);
         return NULL;
     }
diff --git a/src/deque.c b/src/deque.c
index 16f5b5e..cf5cfe3 100644
--- a/src/deque.c
+++ b/src/deque.c
@@ -51,7 +51,7 @@ struct node {
 deque deque_init(const size_t data_size)
 {
     struct _deque *const init = malloc(sizeof(struct _deque));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
@@ -59,13 +59,13 @@ deque deque_init(const size_t data_size)
     init->end_index = init->start_index + 1;
     init->block_count = 1;
     init->block = malloc(sizeof(struct node));
-    if (init->block == NULL) {
+    if (!init->block) {
         free(init);
         return NULL;
     }
     struct node *const block = init->block;
     block->data = malloc(BLOCK_SIZE * init->data_size);
-    if (block->data == NULL) {
+    if (!block->data) {
         free(init->block);
         free(init);
         return NULL;
@@ -114,7 +114,7 @@ int deque_trim(deque me)
     const int end_block = me->end_index / BLOCK_SIZE;
     const int new_block_count = end_block - start_block + 1;
     void *const new_block = malloc(new_block_count * sizeof(struct node));
-    if (new_block == NULL) {
+    if (!new_block) {
         return -ENOMEM;
     }
     for (int i = 0; i < start_block; i++) {
@@ -172,7 +172,7 @@ int deque_push_front(deque me, void *const data)
             const int added_blocks = new_block_count - old_block_count;
             void *temp = realloc(me->block,
                                  new_block_count * sizeof(struct node));
-            if (temp == NULL) {
+            if (!temp) {
                 return -ENOMEM;
             }
             me->block = temp;
@@ -189,9 +189,9 @@ int deque_push_front(deque me, void *const data)
             }
         }
         struct node *const block_item = &me->block[block_index];
-        if (block_item->data == NULL) {
+        if (!block_item->data) {
             block_item->data = malloc(BLOCK_SIZE * me->data_size);
-            if (block_item->data == NULL) {
+            if (!block_item->data) {
                 return -ENOMEM;
             }
         }
@@ -221,7 +221,7 @@ int deque_push_back(deque me, void *const data)
                     (int) ceil(RESIZE_RATIO * me->block_count);
             void *temp = realloc(me->block,
                                  new_block_count * sizeof(struct node));
-            if (temp == NULL) {
+            if (!temp) {
                 return -ENOMEM;
             }
             me->block = temp;
@@ -232,9 +232,9 @@ int deque_push_back(deque me, void *const data)
             }
         }
         struct node *const block_item = &me->block[block_index];
-        if (block_item->data == NULL) {
+        if (!block_item->data) {
             block_item->data = malloc(BLOCK_SIZE * me->data_size);
-            if (block_item->data == NULL) {
+            if (!block_item->data) {
                 return -ENOMEM;
             }
         }
@@ -402,11 +402,11 @@ int deque_get_last(void *const data, deque me)
 int deque_clear(deque me)
 {
     struct node *const temp_block = malloc(sizeof(struct node));
-    if (temp_block == NULL) {
+    if (!temp_block) {
         return -ENOMEM;
     }
     void *const temp_block_data = malloc(BLOCK_SIZE * me->data_size);
-    if (temp_block_data == NULL) {
+    if (!temp_block_data) {
         free(temp_block);
         return -ENOMEM;
     }
diff --git a/src/forward_list.c b/src/forward_list.c
index 5fe4e39..0763a77 100644
--- a/src/forward_list.c
+++ b/src/forward_list.c
@@ -46,7 +46,7 @@ struct node {
 forward_list forward_list_init(const size_t data_size)
 {
     struct _forward_list *const init = malloc(sizeof(struct _forward_list));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
@@ -89,7 +89,7 @@ void forward_list_copy_to_array(void *const arr, forward_list me)
 {
     struct node *traverse = me->head;
     int offset = 0;
-    while (traverse != NULL) {
+    while (traverse) {
         memcpy(arr + offset, traverse->data, me->data_size);
         offset += me->data_size;
         traverse = traverse->next;
@@ -139,11 +139,11 @@ int forward_list_add_at(forward_list me, const int index, void *const data)
         return -EINVAL;
     }
     struct node *const add = malloc(sizeof(struct node));
-    if (add == NULL) {
+    if (!add) {
         return -ENOMEM;
     }
     add->data = malloc(me->data_size);
-    if (add->data == NULL) {
+    if (!add->data) {
         free(add);
         return -ENOMEM;
     }
@@ -347,7 +347,7 @@ int forward_list_get_last(void *const data, forward_list me)
 void forward_list_clear(forward_list me)
 {
     struct node *traverse = me->head;
-    while (traverse != NULL) {
+    while (traverse) {
         struct node *const temp = traverse;
         traverse = traverse->next;
         free(temp->data);
diff --git a/src/list.c b/src/list.c
index ad80d07..8c12fca 100644
--- a/src/list.c
+++ b/src/list.c
@@ -48,7 +48,7 @@ struct node {
 list list_init(const size_t data_size)
 {
     struct _list *const init = malloc(sizeof(struct _list));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
@@ -92,7 +92,7 @@ void list_copy_to_array(void *const arr, list me)
 {
     struct node *traverse = me->head;
     int offset = 0;
-    while (traverse != NULL) {
+    while (traverse) {
         memcpy(arr + offset, traverse->data, me->data_size);
         offset += me->data_size;
         traverse = traverse->next;
@@ -148,22 +148,22 @@ int list_add_first(list me, void *const data)
 {
     struct node *const traverse = me->head;
     struct node *const add = malloc(sizeof(struct node));
-    if (add == NULL) {
+    if (!add) {
         return -ENOMEM;
     }
     add->data = malloc(me->data_size);
-    if (add->data == NULL) {
+    if (!add->data) {
         free(add);
         return -ENOMEM;
     }
     add->prev = NULL;
     memcpy(add->data, data, me->data_size);
     add->next = traverse;
-    if (traverse != NULL) {
+    if (traverse) {
         traverse->prev = add;
     }
     me->head = add;
-    if (me->tail == NULL) {
+    if (!me->tail) {
         me->tail = traverse;
     }
     me->space++;
@@ -195,11 +195,11 @@ int list_add_at(list me, const int index, void *const data)
     // The new node will go right before this node.
     struct node *const traverse = list_get_node_at(me, index);
     struct node *const add = malloc(sizeof(struct node));
-    if (add == NULL) {
+    if (!add) {
         return -ENOMEM;
     }
     add->data = malloc(me->data_size);
-    if (add->data == NULL) {
+    if (!add->data) {
         free(add);
         return -ENOMEM;
     }
@@ -225,18 +225,18 @@ int list_add_last(list me, void *const data)
 {
     struct node *const traverse = me->tail;
     struct node *const add = malloc(sizeof(struct node));
-    if (add == NULL) {
+    if (!add) {
         return -ENOMEM;
     }
     add->data = malloc(me->data_size);
-    if (add->data == NULL) {
+    if (!add->data) {
         free(add);
         return -ENOMEM;
     }
     add->prev = traverse;
     memcpy(add->data, data, me->data_size);
     add->next = NULL;
-    if (traverse != NULL) {
+    if (traverse) {
         traverse->next = add;
     }
     me->tail = add;
@@ -413,7 +413,7 @@ int list_get_last(void *const data, list me)
 void list_clear(list me)
 {
     struct node *traverse = me->head;
-    while (traverse != NULL) {
+    while (traverse) {
         struct node *const temp = traverse;
         traverse = traverse->next;
         free(temp->data);
diff --git a/src/map.c b/src/map.c
index 1302b01..f3b737d 100644
--- a/src/map.c
+++ b/src/map.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Bailey Thompson
+ * Copyright (c) 2017-2018 Bailey Thompson
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -57,7 +57,7 @@ map map_init(const size_t key_size,
              int (*const comparator)(const void *const, const void *const))
 {
     struct _map *const init = malloc(sizeof(struct _map));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -100,7 +100,7 @@ static void map_reference_parent(map me,
                                  struct node *const child)
 {
     child->parent = parent->parent;
-    if (parent->parent == NULL) {
+    if (!parent->parent) {
         me->root = child;
     } else if (parent->parent->left == parent) {
         parent->parent->left = child;
@@ -118,7 +118,7 @@ static void map_rotate_left(map me,
 {
     map_reference_parent(me, parent, child);
     struct node *const grand_child = child->left;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -135,7 +135,7 @@ static void map_rotate_right(map me,
 {
     map_reference_parent(me, parent, child);
     struct node *const grand_child = child->right;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -217,7 +217,7 @@ static void map_insert_balance(map me, struct node *const item)
     struct node *grand_child = NULL;
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance--;
         } else {
@@ -248,19 +248,19 @@ static struct node *map_create_node(map me,
                                     struct node *const parent)
 {
     struct node *const insert = malloc(sizeof(struct node));
-    if (insert == NULL) {
+    if (!insert) {
         return NULL;
     }
     insert->parent = parent;
     insert->balance = 0;
     insert->key = malloc(me->key_size);
-    if (insert->key == NULL) {
+    if (!insert->key) {
         free(insert);
         return NULL;
     }
     memcpy(insert->key, key, me->key_size);
     insert->value = malloc(me->value_size);
-    if (insert->value == NULL) {
+    if (!insert->value) {
         free(insert->key);
         free(insert);
         return NULL;
@@ -285,9 +285,9 @@ static struct node *map_create_node(map me,
  */
 int map_put(map me, void *const key, void *const value)
 {
-    if (me->root == NULL) {
+    if (!me->root) {
         struct node *insert = map_create_node(me, key, value, NULL);
-        if (insert == NULL) {
+        if (!insert) {
             return -ENOMEM;
         }
         me->root = insert;
@@ -297,11 +297,11 @@ int map_put(map me, void *const key, void *const value)
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 struct node *insert = map_create_node(me, key, value, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->left = insert;
@@ -309,11 +309,11 @@ int map_put(map me, void *const key, void *const value)
                 return 0;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 struct node *insert = map_create_node(me, key, value, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->right = insert;
@@ -333,19 +333,19 @@ int map_put(map me, void *const key, void *const value)
 static struct node *map_equal_match(map me, const void *const key)
 {
     struct node *traverse = me->root;
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 return NULL;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 return NULL;
@@ -368,7 +368,7 @@ static struct node *map_equal_match(map me, const void *const key)
 bool map_get(void *const value, map me, void *const key)
 {
     struct node *const traverse = map_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     memcpy(value, traverse->value, me->value_size);
@@ -420,13 +420,13 @@ static void map_delete_balance(map me,
     // Must re-balance if not in {-1, 0, 1}
     if (item->balance > 1 || item->balance < -1) {
         item = map_repair_pivot(me, item, is_left_deleted);
-        if (item->parent == NULL || item->balance == -1 || item->balance == 1) {
+        if (!item->parent || item->balance == -1 || item->balance == 1) {
             return;
         }
     }
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance++;
         } else {
@@ -442,7 +442,7 @@ static void map_delete_balance(map me,
             parent = child->parent;
             // If balance is -1 or +1 after modification or the parent is NULL,
             // then the tree is balanced.
-            if (parent == NULL || child->balance == -1 || child->balance == 1) {
+            if (!parent || child->balance == -1 || child->balance == 1) {
                 return;
             }
         } else {
@@ -459,7 +459,7 @@ static void map_remove_no_children(map me, const struct node *const traverse)
 {
     struct node *const parent = traverse->parent;
     // If no parent and no children, then the only node is traverse.
-    if (parent == NULL) {
+    if (!parent) {
         me->root = NULL;
         return;
     }
@@ -480,8 +480,8 @@ static void map_remove_one_child(map me, const struct node *const traverse)
 {
     struct node *const parent = traverse->parent;
     // If no parent, make the child of traverse the new root.
-    if (parent == NULL) {
-        if (traverse->left != NULL) {
+    if (!parent) {
+        if (traverse->left) {
             traverse->left->parent = NULL;
             me->root = traverse->left;
         } else {
@@ -492,7 +492,7 @@ static void map_remove_one_child(map me, const struct node *const traverse)
     }
     // The parent of traverse now references the child of traverse.
     if (parent->left == traverse) {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->left = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -501,7 +501,7 @@ static void map_remove_one_child(map me, const struct node *const traverse)
         }
         map_delete_balance(me, parent, true);
     } else {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->right = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -529,13 +529,13 @@ static void map_remove_two_children(map me, const struct node *const traverse)
         item->left->parent = item;
     } else {
         item = traverse->right->left;
-        while (item->left != NULL) {
+        while (item->left) {
             item = item->left;
         }
         parent = item->parent;
         item->balance = traverse->balance;
         item->parent->left = item->right;
-        if (item->right != NULL) {
+        if (item->right) {
             item->right->parent = item->parent;
         }
         item->left = traverse->left;
@@ -544,7 +544,7 @@ static void map_remove_two_children(map me, const struct node *const traverse)
         item->right->parent = item;
         item->parent = traverse->parent;
     }
-    if (traverse->parent == NULL) {
+    if (!traverse->parent) {
         me->root = item;
     } else if (traverse->parent->left == traverse) {
         item->parent->left = item;
@@ -559,9 +559,9 @@ static void map_remove_two_children(map me, const struct node *const traverse)
  */
 static void map_remove_element(map me, struct node *const traverse)
 {
-    if (traverse->left == NULL && traverse->right == NULL) {
+    if (!traverse->left && !traverse->right) {
         map_remove_no_children(me, traverse);
-    } else if (traverse->left == NULL || traverse->right == NULL) {
+    } else if (!traverse->left || !traverse->right) {
         map_remove_one_child(me, traverse);
     } else {
         map_remove_two_children(me, traverse);
@@ -583,7 +583,7 @@ static void map_remove_element(map me, struct node *const traverse)
 bool map_remove(map me, void *const key)
 {
     struct node *const traverse = map_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     map_remove_element(me, traverse);
@@ -597,7 +597,7 @@ bool map_remove(map me, void *const key)
  */
 void map_clear(map me)
 {
-    while (me->root != NULL) {
+    while (me->root) {
         map_remove_element(me, me->root);
     }
 }
diff --git a/src/multimap.c b/src/multimap.c
index a15c28e..72d5993 100644
--- a/src/multimap.c
+++ b/src/multimap.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Bailey Thompson
+ * Copyright (c) 2017-2018 Bailey Thompson
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -69,7 +69,7 @@ multimap multimap_init(const size_t key_size,
                                                      const void *const))
 {
     struct _multimap *const init = malloc(sizeof(struct _multimap));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -114,7 +114,7 @@ static void multimap_reference_parent(multimap me,
                                       struct node *const child)
 {
     child->parent = parent->parent;
-    if (parent->parent == NULL) {
+    if (!parent->parent) {
         me->root = child;
     } else if (parent->parent->left == parent) {
         parent->parent->left = child;
@@ -132,7 +132,7 @@ static void multimap_rotate_left(multimap me,
 {
     multimap_reference_parent(me, parent, child);
     struct node *const grand_child = child->left;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -149,7 +149,7 @@ static void multimap_rotate_right(multimap me,
 {
     multimap_reference_parent(me, parent, child);
     struct node *const grand_child = child->right;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -231,7 +231,7 @@ static void multimap_insert_balance(multimap me, struct node *const item)
     struct node *grand_child = NULL;
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance--;
         } else {
@@ -260,11 +260,11 @@ static struct value_node *multimap_create_value_node(multimap me,
                                                      const void *const value)
 {
     struct value_node *const add = malloc(sizeof(struct value_node));
-    if (add == NULL) {
+    if (!add) {
         return NULL;
     }
     add->value = malloc(me->value_size);
-    if (add->value == NULL) {
+    if (!add->value) {
         free(add);
         return NULL;
     }
@@ -282,20 +282,20 @@ static struct node *multimap_create_node(multimap me,
                                          struct node *const parent)
 {
     struct node *const insert = malloc(sizeof(struct node));
-    if (insert == NULL) {
+    if (!insert) {
         return NULL;
     }
     insert->parent = parent;
     insert->balance = 0;
     insert->key = malloc(me->key_size);
-    if (insert->key == NULL) {
+    if (!insert->key) {
         free(insert);
         return NULL;
     }
     memcpy(insert->key, key, me->key_size);
     insert->value_count = 1;
     insert->head = multimap_create_value_node(me, value);
-    if (insert->head == NULL) {
+    if (!insert->head) {
         free(insert->key);
         free(insert);
         return NULL;
@@ -318,9 +318,9 @@ static struct node *multimap_create_node(multimap me,
  */
 int multimap_put(multimap me, void *const key, void *const value)
 {
-    if (me->root == NULL) {
+    if (!me->root) {
         struct node *insert = multimap_create_node(me, key, value, NULL);
-        if (insert == NULL) {
+        if (!insert) {
             return -ENOMEM;
         }
         me->root = insert;
@@ -330,12 +330,12 @@ int multimap_put(multimap me, void *const key, void *const value)
     while (true) {
         const int compare = me->key_comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 struct node *insert =
                         multimap_create_node(me, key, value, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->left = insert;
@@ -343,12 +343,12 @@ int multimap_put(multimap me, void *const key, void *const value)
                 return 0;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 struct node *insert =
                         multimap_create_node(me, key, value, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->right = insert;
@@ -357,7 +357,7 @@ int multimap_put(multimap me, void *const key, void *const value)
             }
         } else {
             struct value_node *value_traverse = traverse->head;
-            while (value_traverse->next != NULL) {
+            while (value_traverse->next) {
                 value_traverse = value_traverse->next;
             }
             value_traverse->next = multimap_create_value_node(me, value);
@@ -374,19 +374,19 @@ int multimap_put(multimap me, void *const key, void *const value)
 static struct node *multimap_equal_match(multimap me, const void *const key)
 {
     struct node *traverse = me->root;
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     while (true) {
         const int compare = me->key_comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 return NULL;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 return NULL;
@@ -408,7 +408,7 @@ static struct node *multimap_equal_match(multimap me, const void *const key)
 void multimap_get_start(multimap me, void *const key)
 {
     const struct node *const traverse = multimap_equal_match(me, key);
-    if (traverse != NULL) {
+    if (traverse) {
         me->iterate_get = traverse->head;
     }
 }
@@ -425,7 +425,7 @@ void multimap_get_start(multimap me, void *const key)
  */
 bool multimap_get_next(void *const value, multimap me)
 {
-    if (me->iterate_get == NULL) {
+    if (!me->iterate_get) {
         return false;
     }
     const struct value_node *const item = me->iterate_get;
@@ -445,7 +445,7 @@ bool multimap_get_next(void *const value, multimap me)
 int multimap_count(multimap me, void *const key)
 {
     struct node *const traverse = multimap_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return 0;
     }
     return traverse->value_count;
@@ -496,13 +496,13 @@ static void multimap_delete_balance(multimap me,
     // Must re-balance if not in {-1, 0, 1}
     if (item->balance > 1 || item->balance < -1) {
         item = multimap_repair_pivot(me, item, is_left_deleted);
-        if (item->parent == NULL || item->balance == -1 || item->balance == 1) {
+        if (!item->parent || item->balance == -1 || item->balance == 1) {
             return;
         }
     }
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance++;
         } else {
@@ -518,7 +518,7 @@ static void multimap_delete_balance(multimap me,
             parent = child->parent;
             // If balance is -1 or +1 after modification or the parent is NULL,
             // then the tree is balanced.
-            if (parent == NULL || child->balance == -1 || child->balance == 1) {
+            if (!parent || child->balance == -1 || child->balance == 1) {
                 return;
             }
         } else {
@@ -536,7 +536,7 @@ static void multimap_remove_no_children(multimap me,
 {
     struct node *const parent = traverse->parent;
     // If no parent and no children, then the only node is traverse.
-    if (parent == NULL) {
+    if (!parent) {
         me->root = NULL;
         return;
     }
@@ -558,8 +558,8 @@ static void multimap_remove_one_child(multimap me,
 {
     struct node *const parent = traverse->parent;
     // If no parent, make the child of traverse the new root.
-    if (parent == NULL) {
-        if (traverse->left != NULL) {
+    if (!parent) {
+        if (traverse->left) {
             traverse->left->parent = NULL;
             me->root = traverse->left;
         } else {
@@ -570,7 +570,7 @@ static void multimap_remove_one_child(multimap me,
     }
     // The parent of traverse now references the child of traverse.
     if (parent->left == traverse) {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->left = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -579,7 +579,7 @@ static void multimap_remove_one_child(multimap me,
         }
         multimap_delete_balance(me, parent, true);
     } else {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->right = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -608,13 +608,13 @@ static void multimap_remove_two_children(multimap me,
         item->left->parent = item;
     } else {
         item = traverse->right->left;
-        while (item->left != NULL) {
+        while (item->left) {
             item = item->left;
         }
         parent = item->parent;
         item->balance = traverse->balance;
         item->parent->left = item->right;
-        if (item->right != NULL) {
+        if (item->right) {
             item->right->parent = item->parent;
         }
         item->left = traverse->left;
@@ -623,7 +623,7 @@ static void multimap_remove_two_children(multimap me,
         item->right->parent = item;
         item->parent = traverse->parent;
     }
-    if (traverse->parent == NULL) {
+    if (!traverse->parent) {
         me->root = item;
     } else if (traverse->parent->left == traverse) {
         item->parent->left = item;
@@ -638,9 +638,9 @@ static void multimap_remove_two_children(multimap me,
  */
 static void multimap_remove_element(multimap me, struct node *const traverse)
 {
-    if (traverse->left == NULL && traverse->right == NULL) {
+    if (!traverse->left && !traverse->right) {
         multimap_remove_no_children(me, traverse);
-    } else if (traverse->left == NULL || traverse->right == NULL) {
+    } else if (!traverse->left || !traverse->right) {
         multimap_remove_one_child(me, traverse);
     } else {
         multimap_remove_two_children(me, traverse);
@@ -661,7 +661,7 @@ static void multimap_remove_element(multimap me, struct node *const traverse)
 bool multimap_remove(multimap me, void *const key, void *const value)
 {
     struct node *const traverse = multimap_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     struct value_node *current = traverse->head;
@@ -670,12 +670,11 @@ bool multimap_remove(multimap me, void *const key, void *const value)
     } else {
         struct value_node *previous = current;
         current = current->next;
-        while (current != NULL &&
-               me->value_comparator(current->value, value) != 0) {
+        while (current && me->value_comparator(current->value, value) != 0) {
             previous = current;
             current = current->next;
         }
-        if (current == NULL) {
+        if (!current) {
             return false;
         }
         previous->next = current->next;
@@ -697,7 +696,7 @@ static void multimap_remove_all_element(multimap me,
                                         struct node *const traverse)
 {
     struct value_node *value_traverse = traverse->head;
-    while (value_traverse != NULL) {
+    while (value_traverse) {
         struct value_node *temp = value_traverse;
         value_traverse = value_traverse->next;
         free(temp->value);
@@ -718,7 +717,7 @@ static void multimap_remove_all_element(multimap me,
 bool multimap_remove_all(multimap me, void *const key)
 {
     struct node *const traverse = multimap_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     multimap_remove_all_element(me, traverse);
@@ -732,7 +731,7 @@ bool multimap_remove_all(multimap me, void *const key)
  */
 void multimap_clear(multimap me)
 {
-    while (me->root != NULL) {
+    while (me->root) {
         multimap_remove_all_element(me, me->root);
     }
 }
diff --git a/src/multiset.c b/src/multiset.c
index b09fb85..ae0a9cd 100644
--- a/src/multiset.c
+++ b/src/multiset.c
@@ -55,7 +55,7 @@ multiset multiset_init(const size_t key_size,
                                                const void *const))
 {
     struct _multiset *const init = malloc(sizeof(struct _multiset));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -97,7 +97,7 @@ static void multiset_reference_parent(multiset me,
                                       struct node *const child)
 {
     child->parent = parent->parent;
-    if (parent->parent == NULL) {
+    if (!parent->parent) {
         me->root = child;
     } else if (parent->parent->left == parent) {
         parent->parent->left = child;
@@ -115,7 +115,7 @@ static void multiset_rotate_left(multiset me,
 {
     multiset_reference_parent(me, parent, child);
     struct node *const grand_child = child->left;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -132,7 +132,7 @@ static void multiset_rotate_right(multiset me,
 {
     multiset_reference_parent(me, parent, child);
     struct node *const grand_child = child->right;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -214,7 +214,7 @@ static void multiset_insert_balance(multiset me, struct node *const item)
     struct node *grand_child = NULL;
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance--;
         } else {
@@ -244,14 +244,14 @@ static struct node *multiset_create_node(multiset me,
                                          struct node *const parent)
 {
     struct node *const insert = malloc(sizeof(struct node));
-    if (insert == NULL) {
+    if (!insert) {
         return NULL;
     }
     insert->count = 1;
     insert->parent = parent;
     insert->balance = 0;
     insert->key = malloc(me->key_size);
-    if (insert->key == NULL) {
+    if (!insert->key) {
         free(insert);
         return NULL;
     }
@@ -273,9 +273,9 @@ static struct node *multiset_create_node(multiset me,
  */
 int multiset_put(multiset me, void *const key)
 {
-    if (me->root == NULL) {
+    if (!me->root) {
         struct node *insert = multiset_create_node(me, key, NULL);
-        if (insert == NULL) {
+        if (!insert) {
             return -ENOMEM;
         }
         me->root = insert;
@@ -285,11 +285,11 @@ int multiset_put(multiset me, void *const key)
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 struct node *insert = multiset_create_node(me, key, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->left = insert;
@@ -297,11 +297,11 @@ int multiset_put(multiset me, void *const key)
                 return 0;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 struct node *insert = multiset_create_node(me, key, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->right = insert;
@@ -322,19 +322,19 @@ int multiset_put(multiset me, void *const key)
 static struct node *multiset_equal_match(multiset me, const void *const key)
 {
     struct node *traverse = me->root;
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 return NULL;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 return NULL;
@@ -356,7 +356,7 @@ static struct node *multiset_equal_match(multiset me, const void *const key)
 int multiset_count(multiset me, void *const key)
 {
     const struct node *const item = multiset_equal_match(me, key);
-    if (item == NULL) {
+    if (!item) {
         return 0;
     }
     return item->count;
@@ -407,13 +407,13 @@ static void multiset_delete_balance(multiset me,
     // Must re-balance if not in {-1, 0, 1}
     if (item->balance > 1 || item->balance < -1) {
         item = multiset_repair_pivot(me, item, is_left_deleted);
-        if (item->parent == NULL || item->balance == -1 || item->balance == 1) {
+        if (!item->parent || item->balance == -1 || item->balance == 1) {
             return;
         }
     }
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance++;
         } else {
@@ -429,7 +429,7 @@ static void multiset_delete_balance(multiset me,
             parent = child->parent;
             // If balance is -1 or +1 after modification or the parent is NULL,
             // then the tree is balanced.
-            if (parent == NULL || child->balance == -1 || child->balance == 1) {
+            if (!parent || child->balance == -1 || child->balance == 1) {
                 return;
             }
         } else {
@@ -447,7 +447,7 @@ static void multiset_remove_no_children(multiset me,
 {
     struct node *const parent = traverse->parent;
     // If no parent and no children, then the only node is traverse.
-    if (parent == NULL) {
+    if (!parent) {
         me->root = NULL;
         return;
     }
@@ -469,8 +469,8 @@ static void multiset_remove_one_child(multiset me,
 {
     struct node *const parent = traverse->parent;
     // If no parent, make the child of traverse the new root.
-    if (parent == NULL) {
-        if (traverse->left != NULL) {
+    if (!parent) {
+        if (traverse->left) {
             traverse->left->parent = NULL;
             me->root = traverse->left;
         } else {
@@ -481,7 +481,7 @@ static void multiset_remove_one_child(multiset me,
     }
     // The parent of traverse now references the child of traverse.
     if (parent->left == traverse) {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->left = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -490,7 +490,7 @@ static void multiset_remove_one_child(multiset me,
         }
         multiset_delete_balance(me, parent, true);
     } else {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->right = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -519,13 +519,13 @@ static void multiset_remove_two_children(multiset me,
         item->left->parent = item;
     } else {
         item = traverse->right->left;
-        while (item->left != NULL) {
+        while (item->left) {
             item = item->left;
         }
         parent = item->parent;
         item->balance = traverse->balance;
         item->parent->left = item->right;
-        if (item->right != NULL) {
+        if (item->right) {
             item->right->parent = item->parent;
         }
         item->left = traverse->left;
@@ -534,7 +534,7 @@ static void multiset_remove_two_children(multiset me,
         item->right->parent = item;
         item->parent = traverse->parent;
     }
-    if (traverse->parent == NULL) {
+    if (!traverse->parent) {
         me->root = item;
     } else if (traverse->parent->left == traverse) {
         item->parent->left = item;
@@ -549,9 +549,9 @@ static void multiset_remove_two_children(multiset me,
  */
 static void multiset_remove_element(multiset me, struct node *const traverse)
 {
-    if (traverse->left == NULL && traverse->right == NULL) {
+    if (!traverse->left && !traverse->right) {
         multiset_remove_no_children(me, traverse);
-    } else if (traverse->left == NULL || traverse->right == NULL) {
+    } else if (!traverse->left || !traverse->right) {
         multiset_remove_one_child(me, traverse);
     } else {
         multiset_remove_two_children(me, traverse);
@@ -571,7 +571,7 @@ static void multiset_remove_element(multiset me, struct node *const traverse)
 bool multiset_remove(multiset me, void *const key)
 {
     struct node *const traverse = multiset_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     traverse->count--;
@@ -593,7 +593,7 @@ bool multiset_remove(multiset me, void *const key)
 bool multiset_remove_all(multiset me, void *const key)
 {
     struct node *const traverse = multiset_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     me->size -= traverse->count;
@@ -608,7 +608,7 @@ bool multiset_remove_all(multiset me, void *const key)
  */
 void multiset_clear(multiset me)
 {
-    while (me->root != NULL) {
+    while (me->root) {
         multiset_remove_element(me, me->root);
     }
     me->size = 0;
diff --git a/src/priority_queue.c b/src/priority_queue.c
index 1cf9968..d94cff3 100644
--- a/src/priority_queue.c
+++ b/src/priority_queue.c
@@ -47,12 +47,12 @@ priority_queue priority_queue_init(const size_t data_size,
                                                      const void *const))
 {
     struct _priority_queue *const init = malloc(sizeof(struct _priority_queue));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
     init->data = vector_init(data_size);
-    if (init->data == NULL) {
+    if (!init->data) {
         free(init);
         return NULL;
     }
@@ -96,7 +96,7 @@ bool priority_queue_is_empty(priority_queue me)
 int priority_queue_push(priority_queue me, void *const data)
 {
     void *const temp = malloc(me->data_size);
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     const int rc = vector_add_last(me->data, data);
diff --git a/src/queue.c b/src/queue.c
index 8a1be19..c45deeb 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -42,12 +42,12 @@ struct _queue {
 queue queue_init(const size_t data_size)
 {
     struct _queue *const init = malloc(sizeof(struct _queue));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->trim_count = 0;
     init->deque_data = deque_init(data_size);
-    if (init->deque_data == NULL) {
+    if (!init->deque_data) {
         free(init);
         return NULL;
     }
diff --git a/src/set.c b/src/set.c
index 16b77bb..35d3d94 100644
--- a/src/set.c
+++ b/src/set.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Bailey Thompson
+ * Copyright (c) 2017-2018 Bailey Thompson
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -52,7 +52,7 @@ set set_init(const size_t key_size,
              int (*const comparator)(const void *const, const void *const))
 {
     struct _set *const init = malloc(sizeof(struct _set));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -94,7 +94,7 @@ static void set_reference_parent(set me,
                                  struct node *const child)
 {
     child->parent = parent->parent;
-    if (parent->parent == NULL) {
+    if (!parent->parent) {
         me->root = child;
     } else if (parent->parent->left == parent) {
         parent->parent->left = child;
@@ -112,7 +112,7 @@ static void set_rotate_left(set me,
 {
     set_reference_parent(me, parent, child);
     struct node *const grand_child = child->left;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -129,7 +129,7 @@ static void set_rotate_right(set me,
 {
     set_reference_parent(me, parent, child);
     struct node *const grand_child = child->right;
-    if (grand_child != NULL) {
+    if (grand_child) {
         grand_child->parent = parent;
     }
     parent->parent = child;
@@ -211,7 +211,7 @@ static void set_insert_balance(set me, struct node *const item)
     struct node *grand_child = NULL;
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance--;
         } else {
@@ -241,13 +241,13 @@ static struct node *set_create_node(set me,
                                     struct node *const parent)
 {
     struct node *const insert = malloc(sizeof(struct node));
-    if (insert == NULL) {
+    if (!insert) {
         return NULL;
     }
     insert->parent = parent;
     insert->balance = 0;
     insert->key = malloc(me->key_size);
-    if (insert->key == NULL) {
+    if (!insert->key) {
         free(insert);
         return NULL;
     }
@@ -269,9 +269,9 @@ static struct node *set_create_node(set me,
  */
 int set_put(set me, void *const key)
 {
-    if (me->root == NULL) {
+    if (!me->root) {
         struct node *insert = set_create_node(me, key, NULL);
-        if (insert == NULL) {
+        if (!insert) {
             return -ENOMEM;
         }
         me->root = insert;
@@ -281,11 +281,11 @@ int set_put(set me, void *const key)
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 struct node *insert = set_create_node(me, key, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->left = insert;
@@ -293,11 +293,11 @@ int set_put(set me, void *const key)
                 return 0;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 struct node *insert = set_create_node(me, key, traverse);
-                if (insert == NULL) {
+                if (!insert) {
                     return -ENOMEM;
                 }
                 traverse->right = insert;
@@ -316,19 +316,19 @@ int set_put(set me, void *const key)
 static struct node *set_equal_match(set me, const void *const key)
 {
     struct node *traverse = me->root;
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     while (true) {
         const int compare = me->comparator(key, traverse->key);
         if (compare < 0) {
-            if (traverse->left != NULL) {
+            if (traverse->left) {
                 traverse = traverse->left;
             } else {
                 return NULL;
             }
         } else if (compare > 0) {
-            if (traverse->right != NULL) {
+            if (traverse->right) {
                 traverse = traverse->right;
             } else {
                 return NULL;
@@ -384,13 +384,13 @@ static void set_delete_balance(set me,
     // Must re-balance if not in {-1, 0, 1}
     if (item->balance > 1 || item->balance < -1) {
         item = set_repair_pivot(me, item, is_left_deleted);
-        if (item->parent == NULL || item->balance == -1 || item->balance == 1) {
+        if (!item->parent || item->balance == -1 || item->balance == 1) {
             return;
         }
     }
     struct node *child = item;
     struct node *parent = item->parent;
-    while (parent != NULL) {
+    while (parent) {
         if (parent->left == child) {
             parent->balance++;
         } else {
@@ -406,7 +406,7 @@ static void set_delete_balance(set me,
             parent = child->parent;
             // If balance is -1 or +1 after modification or the parent is NULL,
             // then the tree is balanced.
-            if (parent == NULL || child->balance == -1 || child->balance == 1) {
+            if (!parent || child->balance == -1 || child->balance == 1) {
                 return;
             }
         } else {
@@ -423,7 +423,7 @@ static void set_remove_no_children(set me, const struct node *const traverse)
 {
     struct node *const parent = traverse->parent;
     // If no parent and no children, then the only node is traverse.
-    if (parent == NULL) {
+    if (!parent) {
         me->root = NULL;
         return;
     }
@@ -444,8 +444,8 @@ static void set_remove_one_child(set me, const struct node *const traverse)
 {
     struct node *const parent = traverse->parent;
     // If no parent, make the child of traverse the new root.
-    if (parent == NULL) {
-        if (traverse->left != NULL) {
+    if (!parent) {
+        if (traverse->left) {
             traverse->left->parent = NULL;
             me->root = traverse->left;
         } else {
@@ -456,7 +456,7 @@ static void set_remove_one_child(set me, const struct node *const traverse)
     }
     // The parent of traverse now references the child of traverse.
     if (parent->left == traverse) {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->left = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -465,7 +465,7 @@ static void set_remove_one_child(set me, const struct node *const traverse)
         }
         set_delete_balance(me, parent, true);
     } else {
-        if (traverse->left != NULL) {
+        if (traverse->left) {
             parent->right = traverse->left;
             traverse->left->parent = parent;
         } else {
@@ -493,13 +493,13 @@ static void set_remove_two_children(set me, const struct node *const traverse)
         item->left->parent = item;
     } else {
         item = traverse->right->left;
-        while (item->left != NULL) {
+        while (item->left) {
             item = item->left;
         }
         parent = item->parent;
         item->balance = traverse->balance;
         item->parent->left = item->right;
-        if (item->right != NULL) {
+        if (item->right) {
             item->right->parent = item->parent;
         }
         item->left = traverse->left;
@@ -508,7 +508,7 @@ static void set_remove_two_children(set me, const struct node *const traverse)
         item->right->parent = item;
         item->parent = traverse->parent;
     }
-    if (traverse->parent == NULL) {
+    if (!traverse->parent) {
         me->root = item;
     } else if (traverse->parent->left == traverse) {
         item->parent->left = item;
@@ -523,9 +523,9 @@ static void set_remove_two_children(set me, const struct node *const traverse)
  */
 static void set_remove_element(set me, struct node *const traverse)
 {
-    if (traverse->left == NULL && traverse->right == NULL) {
+    if (!traverse->left && !traverse->right) {
         set_remove_no_children(me, traverse);
-    } else if (traverse->left == NULL || traverse->right == NULL) {
+    } else if (!traverse->left || !traverse->right) {
         set_remove_one_child(me, traverse);
     } else {
         set_remove_two_children(me, traverse);
@@ -546,7 +546,7 @@ static void set_remove_element(set me, struct node *const traverse)
 bool set_remove(set me, void *const key)
 {
     struct node *const traverse = set_equal_match(me, key);
-    if (traverse == NULL) {
+    if (!traverse) {
         return false;
     }
     set_remove_element(me, traverse);
@@ -560,7 +560,7 @@ bool set_remove(set me, void *const key)
  */
 void set_clear(set me)
 {
-    while (me->root != NULL) {
+    while (me->root) {
         set_remove_element(me, me->root);
     }
 }
diff --git a/src/stack.c b/src/stack.c
index 026659e..60a1905 100644
--- a/src/stack.c
+++ b/src/stack.c
@@ -39,11 +39,11 @@ struct _stack {
 stack stack_init(const size_t data_size)
 {
     struct _stack *const init = malloc(sizeof(struct _stack));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->deque_data = deque_init(data_size);
-    if (init->deque_data == NULL) {
+    if (!init->deque_data) {
         free(init);
         return NULL;
     }
diff --git a/src/unordered_map.c b/src/unordered_map.c
index bf6aff4..6acff17 100644
--- a/src/unordered_map.c
+++ b/src/unordered_map.c
@@ -65,7 +65,7 @@ unordered_map unordered_map_init(const size_t key_size,
                                                    const void *const))
 {
     struct _unordered_map *const init = malloc(sizeof(struct _unordered_map));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -75,7 +75,7 @@ unordered_map unordered_map_init(const size_t key_size,
     init->size = 0;
     init->capacity = STARTING_BUCKETS;
     init->buckets = calloc(STARTING_BUCKETS, sizeof(struct node *));
-    if (init->buckets == NULL) {
+    if (!init->buckets) {
         free(init);
         return NULL;
     }
@@ -89,12 +89,12 @@ static void unordered_map_add_item(unordered_map me, struct node *const add)
 {
     const int index = (int) (add->hash % me->capacity);
     add->next = NULL;
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = add;
         return;
     }
     struct node *traverse = me->buckets[index];
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         traverse = traverse->next;
     }
     traverse->next = add;
@@ -113,13 +113,13 @@ int unordered_map_rehash(unordered_map me)
 {
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) me->capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             traverse->hash = me->hash(traverse->key);
             unordered_map_add_item(me, traverse);
@@ -163,14 +163,14 @@ static int unordered_map_resize(unordered_map me)
     const int new_capacity = (int) (me->capacity * RESIZE_RATIO);
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) new_capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     me->capacity = new_capacity;
     for (int i = 0; i < old_capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             unordered_map_add_item(me, traverse);
             traverse = backup;
@@ -200,17 +200,17 @@ static struct node *const unordered_map_create_element(unordered_map me,
                                                        const void *const value)
 {
     struct node *const init = malloc(sizeof(struct node));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key = malloc(me->key_size);
-    if (init->key == NULL) {
+    if (!init->key) {
         free(init);
         return NULL;
     }
     memcpy(init->key, key, me->key_size);
     init->value = malloc(me->value_size);
-    if (init->value == NULL) {
+    if (!init->value) {
         free(init->key);
         free(init);
         return NULL;
@@ -237,9 +237,9 @@ int unordered_map_put(unordered_map me, void *const key, void *const value)
 
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = unordered_map_create_element(me, hash, key, value);
-        if (me->buckets[index] == NULL) {
+        if (!me->buckets[index]) {
             return -ENOMEM;
         }
     } else {
@@ -248,7 +248,7 @@ int unordered_map_put(unordered_map me, void *const key, void *const value)
             memcpy(traverse->value, value, me->value_size);
             return 0;
         }
-        while (traverse->next != NULL) {
+        while (traverse->next) {
             traverse = traverse->next;
             if (unordered_map_is_equal(me, traverse, hash, key)) {
                 memcpy(traverse->value, value, me->value_size);
@@ -256,7 +256,7 @@ int unordered_map_put(unordered_map me, void *const key, void *const value)
             }
         }
         traverse->next = unordered_map_create_element(me, hash, key, value);
-        if (traverse->next == NULL) {
+        if (!traverse->next) {
             return -ENOMEM;
         }
     }
@@ -281,7 +281,7 @@ bool unordered_map_get(void *const value, unordered_map me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_map_is_equal(me, traverse, hash, key)) {
             memcpy(value, traverse->value, me->value_size);
             return true;
@@ -304,7 +304,7 @@ bool unordered_map_contains(unordered_map me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     const struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_map_is_equal(me, traverse, hash, key)) {
             return true;
         }
@@ -325,7 +325,7 @@ bool unordered_map_remove(unordered_map me, void *const key)
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         return false;
     }
     struct node *traverse = me->buckets[index];
@@ -337,7 +337,7 @@ bool unordered_map_remove(unordered_map me, void *const key)
         me->size--;
         return true;
     }
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         if (unordered_map_is_equal(me, traverse->next, hash, key)) {
             struct node *const backup = traverse->next;
             traverse->next = traverse->next->next;
@@ -364,12 +364,12 @@ int unordered_map_clear(unordered_map me)
 {
     struct node **temp =
             calloc((size_t) STARTING_BUCKETS, sizeof(struct node *));
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse;
             traverse = traverse->next;
             free(backup->key);
diff --git a/src/unordered_multimap.c b/src/unordered_multimap.c
index ee1abea..876b130 100644
--- a/src/unordered_multimap.c
+++ b/src/unordered_multimap.c
@@ -74,7 +74,7 @@ unordered_multimap_init(const size_t key_size,
 {
     struct _unordered_multimap *const init =
             malloc(sizeof(struct _unordered_multimap));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -85,13 +85,13 @@ unordered_multimap_init(const size_t key_size,
     init->size = 0;
     init->capacity = STARTING_BUCKETS;
     init->buckets = calloc(STARTING_BUCKETS, sizeof(struct node *));
-    if (init->buckets == NULL) {
+    if (!init->buckets) {
         free(init);
         return NULL;
     }
     init->iterate_hash = 0;
     init->iterate_key = calloc(1, init->key_size);
-    if (init->iterate_key == NULL) {
+    if (!init->iterate_key) {
         free(init->buckets);
         free(init);
         return NULL;
@@ -108,12 +108,12 @@ static void unordered_multimap_add_item(unordered_multimap me,
 {
     const int index = (int) (add->hash % me->capacity);
     add->next = NULL;
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = add;
         return;
     }
     struct node *traverse = me->buckets[index];
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         traverse = traverse->next;
     }
     traverse->next = add;
@@ -132,13 +132,13 @@ int unordered_multimap_rehash(unordered_multimap me)
 {
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) me->capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             traverse->hash = me->hash(traverse->key);
             unordered_multimap_add_item(me, traverse);
@@ -182,14 +182,14 @@ static int unordered_multimap_resize(unordered_multimap me)
     const int new_capacity = (int) (me->capacity * RESIZE_RATIO);
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) new_capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     me->capacity = new_capacity;
     for (int i = 0; i < old_capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             unordered_multimap_add_item(me, traverse);
             traverse = backup;
@@ -220,17 +220,17 @@ unordered_multimap_create_element(unordered_multimap me,
                                   const void *const value)
 {
     struct node *const init = malloc(sizeof(struct node));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key = malloc(me->key_size);
-    if (init->key == NULL) {
+    if (!init->key) {
         free(init);
         return NULL;
     }
     memcpy(init->key, key, me->key_size);
     init->value = malloc(me->value_size);
-    if (init->value == NULL) {
+    if (!init->value) {
         free(init->key);
         free(init);
         return NULL;
@@ -257,20 +257,20 @@ int unordered_multimap_put(unordered_multimap me,
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] =
                 unordered_multimap_create_element(me, hash, key, value);
-        if (me->buckets[index] == NULL) {
+        if (!me->buckets[index]) {
             return -ENOMEM;
         }
     } else {
         struct node *traverse = me->buckets[index];
-        while (traverse->next != NULL) {
+        while (traverse->next) {
             traverse = traverse->next;
         }
         traverse->next =
                 unordered_multimap_create_element(me, hash, key, value);
-        if (traverse->next == NULL) {
+        if (!traverse->next) {
             return -ENOMEM;
         }
     }
@@ -296,7 +296,7 @@ void unordered_multimap_get_start(unordered_multimap me, void *const key)
     me->iterate_element = NULL;
     const int index = (int) (me->iterate_hash % me->capacity);
     struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_multimap_is_equal(me, traverse, me->iterate_hash, key)) {
             me->iterate_element = traverse;
             return;
@@ -318,12 +318,12 @@ void unordered_multimap_get_start(unordered_multimap me, void *const key)
  */
 bool unordered_multimap_get_next(void *const value, unordered_multimap me)
 {
-    if (me->iterate_element == NULL) {
+    if (!me->iterate_element) {
         return false;
     }
     struct node *const item = me->iterate_element;
     struct node *traverse = item->next;
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_multimap_is_equal(me, traverse, me->iterate_hash,
                                         me->iterate_key)) {
             me->iterate_element = traverse;
@@ -351,7 +351,7 @@ int unordered_multimap_count(unordered_multimap me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     const struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_multimap_is_equal(me, traverse, hash, key)) {
             count++;
         }
@@ -373,7 +373,7 @@ bool unordered_multimap_contains(unordered_multimap me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     const struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_multimap_is_equal(me, traverse, hash, key)) {
             return true;
         }
@@ -397,7 +397,7 @@ bool unordered_multimap_remove(unordered_multimap me,
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         return false;
     }
     struct node *traverse = me->buckets[index];
@@ -410,7 +410,7 @@ bool unordered_multimap_remove(unordered_multimap me,
         me->size--;
         return true;
     }
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         is_key_equal =
                 unordered_multimap_is_equal(me, traverse->next, hash, key);
         if (is_key_equal && me->value_comparator(traverse->value, value) == 0) {
@@ -443,7 +443,7 @@ bool unordered_multimap_remove_all(unordered_multimap me, void *const key)
     bool was_modified = false;
     while (true) {
         struct node *traverse = me->buckets[index];
-        if (traverse == NULL) {
+        if (!traverse) {
             break;
         }
         if (unordered_multimap_is_equal(me, traverse, hash, key)) {
@@ -455,7 +455,7 @@ bool unordered_multimap_remove_all(unordered_multimap me, void *const key)
             was_modified = true;
             continue;
         }
-        while (traverse->next != NULL) {
+        while (traverse->next) {
             if (unordered_multimap_is_equal(me, traverse->next, hash, key)) {
                 struct node *const backup = traverse->next;
                 traverse->next = traverse->next->next;
@@ -485,12 +485,12 @@ int unordered_multimap_clear(unordered_multimap me)
 {
     struct node **temp =
             calloc((size_t) STARTING_BUCKETS, sizeof(struct node *));
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse;
             traverse = traverse->next;
             free(backup->key);
diff --git a/src/unordered_multiset.c b/src/unordered_multiset.c
index 948b2a3..b118c3e 100644
--- a/src/unordered_multiset.c
+++ b/src/unordered_multiset.c
@@ -64,7 +64,7 @@ unordered_multiset_init(const size_t key_size,
 {
     struct _unordered_multiset *const init =
             malloc(sizeof(struct _unordered_multiset));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -74,7 +74,7 @@ unordered_multiset_init(const size_t key_size,
     init->used = 0;
     init->capacity = STARTING_BUCKETS;
     init->buckets = calloc(STARTING_BUCKETS, sizeof(struct node *));
-    if (init->buckets == NULL) {
+    if (!init->buckets) {
         free(init);
         return NULL;
     }
@@ -89,12 +89,12 @@ static void unordered_multiset_add_item(unordered_multiset me,
 {
     const int index = (int) (add->hash % me->capacity);
     add->next = NULL;
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = add;
         return;
     }
     struct node *traverse = me->buckets[index];
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         traverse = traverse->next;
     }
     traverse->next = add;
@@ -113,13 +113,13 @@ int unordered_multiset_rehash(unordered_multiset me)
 {
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) me->capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             traverse->hash = me->hash(traverse->key);
             unordered_multiset_add_item(me, traverse);
@@ -163,14 +163,14 @@ static int unordered_multiset_resize(unordered_multiset me)
     const int new_capacity = (int) (me->capacity * RESIZE_RATIO);
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) new_capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     me->capacity = new_capacity;
     for (int i = 0; i < old_capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             unordered_multiset_add_item(me, traverse);
             traverse = backup;
@@ -200,12 +200,12 @@ unordered_multiset_create_element(unordered_multiset me,
                                   const void *const key)
 {
     struct node *const init = malloc(sizeof(struct node));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->count = 1;
     init->key = malloc(me->key_size);
-    if (init->key == NULL) {
+    if (!init->key) {
         free(init);
         return NULL;
     }
@@ -229,9 +229,9 @@ int unordered_multiset_put(unordered_multiset me, void *const key)
 
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = unordered_multiset_create_element(me, hash, key);
-        if (me->buckets[index] == NULL) {
+        if (!me->buckets[index]) {
             return -ENOMEM;
         }
     } else {
@@ -241,7 +241,7 @@ int unordered_multiset_put(unordered_multiset me, void *const key)
             me->size++;
             return 0;
         }
-        while (traverse->next != NULL) {
+        while (traverse->next) {
             traverse = traverse->next;
             if (unordered_multiset_is_equal(me, traverse, hash, key)) {
                 traverse->count++;
@@ -250,7 +250,7 @@ int unordered_multiset_put(unordered_multiset me, void *const key)
             }
         }
         traverse->next = unordered_multiset_create_element(me, hash, key);
-        if (traverse->next == NULL) {
+        if (!traverse->next) {
             return -ENOMEM;
         }
     }
@@ -275,7 +275,7 @@ int unordered_multiset_count(unordered_multiset me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     const struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_multiset_is_equal(me, traverse, hash, key)) {
             return traverse->count;
         }
@@ -309,7 +309,7 @@ bool unordered_multiset_remove(unordered_multiset me, void *const key)
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         return false;
     }
     struct node *traverse = me->buckets[index];
@@ -324,7 +324,7 @@ bool unordered_multiset_remove(unordered_multiset me, void *const key)
         me->size--;
         return true;
     }
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         if (unordered_multiset_is_equal(me, traverse->next, hash, key)) {
             struct node *const backup = traverse->next;
             backup->count--;
@@ -355,7 +355,7 @@ bool unordered_multiset_remove_all(unordered_multiset me, void *const key)
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         return false;
     }
     struct node *traverse = me->buckets[index];
@@ -367,7 +367,7 @@ bool unordered_multiset_remove_all(unordered_multiset me, void *const key)
         me->used--;
         return true;
     }
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         if (unordered_multiset_is_equal(me, traverse->next, hash, key)) {
             struct node *const backup = traverse->next;
             traverse->next = traverse->next->next;
@@ -394,12 +394,12 @@ int unordered_multiset_clear(unordered_multiset me)
 {
     struct node **temp =
             calloc((size_t) STARTING_BUCKETS, sizeof(struct node *));
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse;
             traverse = traverse->next;
             free(backup->key);
diff --git a/src/unordered_set.c b/src/unordered_set.c
index fda5a51..78b8f25 100644
--- a/src/unordered_set.c
+++ b/src/unordered_set.c
@@ -61,7 +61,7 @@ unordered_set unordered_set_init(const size_t key_size,
                                                    const void *const))
 {
     struct _unordered_set *const init = malloc(sizeof(struct _unordered_set));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key_size = key_size;
@@ -70,7 +70,7 @@ unordered_set unordered_set_init(const size_t key_size,
     init->size = 0;
     init->capacity = STARTING_BUCKETS;
     init->buckets = calloc(STARTING_BUCKETS, sizeof(struct node *));
-    if (init->buckets == NULL) {
+    if (!init->buckets) {
         free(init);
         return NULL;
     }
@@ -84,12 +84,12 @@ static void unordered_set_add_item(unordered_set me, struct node *const add)
 {
     const int index = (int) (add->hash % me->capacity);
     add->next = NULL;
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = add;
         return;
     }
     struct node *traverse = me->buckets[index];
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         traverse = traverse->next;
     }
     traverse->next = add;
@@ -108,13 +108,13 @@ int unordered_set_rehash(unordered_set me)
 {
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) me->capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             traverse->hash = me->hash(traverse->key);
             unordered_set_add_item(me, traverse);
@@ -158,14 +158,14 @@ static int unordered_set_resize(unordered_set me)
     const int new_capacity = (int) (me->capacity * RESIZE_RATIO);
     struct node **old_buckets = me->buckets;
     me->buckets = calloc((size_t) new_capacity, sizeof(struct node *));
-    if (me->buckets == NULL) {
+    if (!me->buckets) {
         me->buckets = old_buckets;
         return -ENOMEM;
     }
     me->capacity = new_capacity;
     for (int i = 0; i < old_capacity; i++) {
         struct node *traverse = old_buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse->next;
             unordered_set_add_item(me, traverse);
             traverse = backup;
@@ -194,11 +194,11 @@ static struct node *const unordered_set_create_element(unordered_set me,
                                                        const void *const key)
 {
     struct node *const init = malloc(sizeof(struct node));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->key = malloc(me->key_size);
-    if (init->key == NULL) {
+    if (!init->key) {
         free(init);
         return NULL;
     }
@@ -223,9 +223,9 @@ int unordered_set_put(unordered_set me, void *const key)
 
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         me->buckets[index] = unordered_set_create_element(me, hash, key);
-        if (me->buckets[index] == NULL) {
+        if (!me->buckets[index]) {
             return -ENOMEM;
         }
     } else {
@@ -233,14 +233,14 @@ int unordered_set_put(unordered_set me, void *const key)
         if (unordered_set_is_equal(me, traverse, hash, key)) {
             return 0;
         }
-        while (traverse->next != NULL) {
+        while (traverse->next) {
             traverse = traverse->next;
             if (unordered_set_is_equal(me, traverse, hash, key)) {
                 return 0;
             }
         }
         traverse->next = unordered_set_create_element(me, hash, key);
-        if (traverse->next == NULL) {
+        if (!traverse->next) {
             return -ENOMEM;
         }
     }
@@ -264,7 +264,7 @@ bool unordered_set_contains(unordered_set me, void *const key)
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
     const struct node *traverse = me->buckets[index];
-    while (traverse != NULL) {
+    while (traverse) {
         if (unordered_set_is_equal(me, traverse, hash, key)) {
             return true;
         }
@@ -285,7 +285,7 @@ bool unordered_set_remove(unordered_set me, void *const key)
 {
     const unsigned long hash = me->hash(key);
     const int index = (int) (hash % me->capacity);
-    if (me->buckets[index] == NULL) {
+    if (!me->buckets[index]) {
         return false;
     }
     struct node *traverse = me->buckets[index];
@@ -296,7 +296,7 @@ bool unordered_set_remove(unordered_set me, void *const key)
         me->size--;
         return true;
     }
-    while (traverse->next != NULL) {
+    while (traverse->next) {
         if (unordered_set_is_equal(me, traverse->next, hash, key)) {
             struct node *const backup = traverse->next;
             traverse->next = traverse->next->next;
@@ -322,12 +322,12 @@ int unordered_set_clear(unordered_set me)
 {
     struct node **temp =
             calloc((size_t) STARTING_BUCKETS, sizeof(struct node *));
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     for (int i = 0; i < me->capacity; i++) {
         struct node *traverse = me->buckets[i];
-        while (traverse != NULL) {
+        while (traverse) {
             struct node *const backup = traverse;
             traverse = traverse->next;
             free(backup->key);
diff --git a/src/vector.c b/src/vector.c
index 5ca2b86..6e18893 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -45,14 +45,14 @@ struct _vector {
 vector vector_init(const size_t data_size)
 {
     struct _vector *const init = malloc(sizeof(struct _vector));
-    if (init == NULL) {
+    if (!init) {
         return NULL;
     }
     init->data_size = data_size;
     init->offset = 0;
     init->space = START_SPACE;
     init->storage = malloc(init->space * init->data_size);
-    if (init->storage == NULL) {
+    if (!init->storage) {
         free(init);
         return NULL;
     }
@@ -89,7 +89,7 @@ bool vector_is_empty(vector me)
 static int vector_set_space(vector me, const int size)
 {
     void *const temp = realloc(me->storage, size * me->data_size);
-    if (temp == NULL) {
+    if (!temp) {
         return -ENOMEM;
     }
     me->storage = temp;
@@ -190,7 +190,7 @@ int vector_add_at(vector me, const int index, void *const data)
     if (me->offset + 1 >= me->space) {
         const int new_space = (int) (me->space * RESIZE_RATIO);
         void *const temp = realloc(me->storage, new_space * me->data_size);
-        if (temp == NULL) {
+        if (!temp) {
             return -ENOMEM;
         }
         me->storage = temp;