Calculate the size of a binary tree

1 files changed, 52 insertions, 0 deletions

diff --git a/src/02/03/stack.c b/src/02/03/stack.c
new file mode 100644
index 0000000..ba3655d
--- /dev/null
+++ b/src/02/03/stack.c
@@ -0,0 +1,52 @@
+#include "stack.h"
+#include <stdlib.h>
+
+Node *node_init(void *data) {
+  Node *node = malloc(sizeof(Node));
+  node->next = NULL;
+  node->data = data;
+  return node;
+}
+
+Stack *stack_init() {
+  Stack *stack = malloc(sizeof(Stack));
+  stack->head = NULL;
+  return stack;
+}
+
+int stack_size(Stack *self) {
+  if (!self || !self->head)
+    return 0;
+
+  int count = 0;
+  Node *current = self->head;
+  while (current) {
+    ++count;
+    current = current->next;
+  }
+
+  return count;
+}
+
+void *stack_peek(Stack *self) {
+  if (self->head)
+    return self->head->data;
+  return NULL;
+}
+
+void stack_push(Stack *stack, void *data) {
+  Node *node = node_init(data);
+  node->next = stack->head;
+  stack->head = node;
+}
+
+void *stack_pop(Stack *self) {
+  if (self->head) {
+    Node *tmp = self->head;
+    void *data = tmp->data;
+    self->head = self->head->next;
+    free(tmp);
+    return data;
+  }
+  return NULL;
+}