stack implementation by linkedlist

data_structures/stack/stack_linkedlist/stack.c

@@ -0,0 +1,79 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "stack.h"
+
+#define T Stack_T
+
+typedef struct elem {
+    void *val;
+	struct elem *next;
+} elem_t;
+
+struct T {
+    int count;
+	elem_t *head;
+};
+
+/* Initial stack */
+T Stack_init (void) {
+    T stack;
+	stack = (T) malloc(sizeof(T));
+	stack->count = 0;
+	stack->head = NULL;
+	return stack;
+}
+
+/* Check empty stack*/
+int Stack_empty(T stack) {
+    assert(stack);
+	return stack->count == 0;
+}
+
+/* Return size of the stack */
+int Stack_size(T stack) {
+    assert(stack);
+	return stack->count;
+}
+
+/* Push an element into the stack */
+void Stack_push(T stack, void *val) {
+    elem_t *t;
+
+	assert(stack);
+	t = (elem_t *) malloc(sizeof(elem_t));
+	t->val = val;
+    t->next = stack->head;
+	stack->head = t;
+	stack->count++;
+}
+
+/* Pop an element out of the stack */
+void *Stack_pop(T stack) {
+    void *val;
+	elem_t *t;
+
+	assert(stack);
+	assert(stack->count > 0);
+	t = stack->head;
+	stack->head = t->next;
+    stack->count--;
+	val = t->val;
+	free(t);
+	return val;
+}
+
+/* Print all elements in the stack */
+void Stack_print(Stack_T stack) {
+    assert(stack);
+
+    int i, size = Stack_size(stack);
+	elem_t *current_elem = stack->head;
+	printf("Stack [Top --- Bottom]: ");
+	for(i = 0; i < size; ++i) {
+	    printf("%p ", (int *)current_elem->val);
+		current_elem = current_elem->next;
+	}
+	printf("\n");
+}