From 2e58bc22071f12027af5f2d8b428f77172df36d5 Mon Sep 17 00:00:00 2001
From: dang hai <haihoangdang91@gmail.com>
Date: Mon, 1 Jul 2019 18:06:21 -0700
Subject: [PATCH] stack implementation by linkedlist

---
 data_structures/stack/README.md               |  7 +-
 .../stack/stack_linkedlist/Makefile           | 12 +++
 data_structures/stack/stack_linkedlist/main.c | 22 ++++++
 .../stack/stack_linkedlist/stack.c            | 79 +++++++++++++++++++
 .../stack/stack_linkedlist/stack.h            | 15 ++++
 5 files changed, 132 insertions(+), 3 deletions(-)
 create mode 100644 data_structures/stack/stack_linkedlist/Makefile
 create mode 100644 data_structures/stack/stack_linkedlist/main.c
 create mode 100644 data_structures/stack/stack_linkedlist/stack.c
 create mode 100644 data_structures/stack/stack_linkedlist/stack.h

diff --git a/data_structures/stack/README.md b/data_structures/stack/README.md
index 174e9454..18bd2fb1 100644
--- a/data_structures/stack/README.md
+++ b/data_structures/stack/README.md
@@ -1,4 +1,4 @@
-# Simple generic Stack 
+# Simple generic Stack
 
 This is a modular generic stack data-structure. The stack is self growing.
 
@@ -6,7 +6,8 @@ This is a modular generic stack data-structure. The stack is self growing.
 
 * stack-Header file for import.
 * stack.c implementation of the stack
-* main.c framework program for testing. 
+* main.c framework program for testing.
+* stack_linkedlist: Another stack implementation by linkedlist
 
 You need to only import the **stack.h**
 
@@ -18,7 +19,7 @@ Initializes the stack with a capacity of 10 elements.
 
 ``` void push(void * object); ```
 
-pushs the argument onto the stack 
+pushs the argument onto the stack
 
 ``` void  * pop(); ```
 
diff --git a/data_structures/stack/stack_linkedlist/Makefile b/data_structures/stack/stack_linkedlist/Makefile
new file mode 100644
index 00000000..1fcb6fd8
--- /dev/null
+++ b/data_structures/stack/stack_linkedlist/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
diff --git a/data_structures/stack/stack_linkedlist/main.c b/data_structures/stack/stack_linkedlist/main.c
new file mode 100644
index 00000000..6c8d1477
--- /dev/null
+++ b/data_structures/stack/stack_linkedlist/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;
+}
diff --git a/data_structures/stack/stack_linkedlist/stack.c b/data_structures/stack/stack_linkedlist/stack.c
new file mode 100644
index 00000000..1e4750b3
--- /dev/null
+++ b/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");
+}
diff --git a/data_structures/stack/stack_linkedlist/stack.h b/data_structures/stack/stack_linkedlist/stack.h
new file mode 100644
index 00000000..ba82ed21
--- /dev/null
+++ b/data_structures/stack/stack_linkedlist/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