Fix filenames for DIRECTORY.md

data_structures/stack/stack_linked_list/Makefile

@@ -0,0 +1,12 @@
+CC = gcc
+CFLAGS = -c -Wall
+
+all: main
+main: main.o stack.o
+	$(CC) main.o stack.o -o  main
+
+stack.o: stack.c
+	$(CC) $(CFLAGS) stack.c
+
+clean:
+	rm *o main

data_structures/stack/stack_linked_list/main.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "stack.h"
+
+int main() {
+    Stack_T stk;
+    stk = Stack_init();
+    Stack_push(stk, (int *) 1);
+    Stack_push(stk, (int *) 2);
+    Stack_push(stk, (int *) 3);
+    Stack_push(stk, (int *) 4);
+    printf("Size: %d\n", Stack_size(stk));
+    Stack_print(stk);
+    Stack_pop(stk);
+    printf("Stack after popping: \n");
+    Stack_print(stk);
+    Stack_pop(stk);
+    printf("Stack after popping: \n");
+    Stack_print(stk);
+    return 0;
+}

data_structures/stack/stack_linked_list/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");
+}

data_structures/stack/stack_linked_list/stack.h

@@ -0,0 +1,15 @@
+#ifndef __STACK__
+#define __STACK__
+
+#define T Stack_T
+typedef struct T *T;
+
+extern T     Stack_init   (void);
+extern int   Stack_size   (T stack);
+extern int   Stack_empty  (T stack);
+extern void  Stack_push   (T stack, void *val);
+extern void *Stack_pop    (T stack);
+extern void  Stack_print  (T stack);
+
+#undef T
+#endif