stack implementation using linked list in c

1#include <stdio.h>
2#include <stdlib.h>
3#define TRUE 1
4#define FALSE 0
5
6struct node
7{
8    int data;
9    struct node *next;
10};
11typedef struct node node;
12
13node *top;
14
15void initialize()
16{
17    top = NULL;
18}
19
20void push(int value)
21{
22    node *tmp;
23    tmp = malloc(sizeof(node));
24    tmp -> data = value;
25    tmp -> next = top;
26    top = tmp;
27}
28
29int pop()
30{
31    node *tmp;
32    int n;
33    tmp = top;
34    n = tmp->data;
35    top = top->next;
36    free(tmp);
37    return n;
38}
39
40int Top()
41{
42    return top->data;
43}
44
45int isempty()
46{
47    return top==NULL;
48}
49
50void display(node *head)
51{
52    if(head == NULL)
53    {
54        printf("NULL\n");
55    }
56    else
57    {
58        printf("%d\n", head -> data);
59        display(head->next);
60    }
61}
62
63int main()
64{
65    initialize();
66    push(10);
67    push(20);
68    push(30);
69    printf("The top is %d\n",Top());
70    pop();
71    printf("The top after pop is %d\n",Top());
72    display(top);
73    return 0;
74}
75

1/*
2 * C Program to Implement a Stack using Linked List
3 */
4#include <stdio.h>
5#include <stdlib.h>
6 
7struct node
8{
9    int info;
10    struct node *ptr;
11}*top,*top1,*temp;
12 
13int topelement();
14void push(int data);
15void pop();
16void empty();
17void display();
18void destroy();
19void stack_count();
20void create();
21 
22int count = 0;
23 
24void main()
25{
26    int no, ch, e;
27 
28    printf("\n 1 - Push");
29    printf("\n 2 - Pop");
30    printf("\n 3 - Top");
31    printf("\n 4 - Empty");
32    printf("\n 5 - Exit");
33    printf("\n 6 - Dipslay");
34    printf("\n 7 - Stack Count");
35    printf("\n 8 - Destroy stack");
36 
37    create();
38 
39    while (1)
40    {
41        printf("\n Enter choice : ");
42        scanf("%d", &ch);
43 
44        switch (ch)
45        {
46        case 1:
47            printf("Enter data : ");
48            scanf("%d", &no);
49            push(no);
50            break;
51        case 2:
52            pop();
53            break;
54        case 3:
55            if (top == NULL)
56                printf("No elements in stack");
57            else
58            {
59                e = topelement();
60                printf("\n Top element : %d", e);
61            }
62            break;
63        case 4:
64            empty();
65            break;
66        case 5:
67            exit(0);
68        case 6:
69            display();
70            break;
71        case 7:
72            stack_count();
73            break;
74        case 8:
75            destroy();
76            break;
77        default :
78            printf(" Wrong choice, Please enter correct choice  ");
79            break;
80        }
81    }
82}
83 
84/* Create empty stack */
85void create()
86{
87    top = NULL;
88}
89 
90/* Count stack elements */
91void stack_count()
92{
93    printf("\n No. of elements in stack : %d", count);
94}
95 
96/* Push data into stack */
97void push(int data)
98{
99    if (top == NULL)
100    {
101        top =(struct node *)malloc(1*sizeof(struct node));
102        top->ptr = NULL;
103        top->info = data;
104    }
105    else
106    {
107        temp =(struct node *)malloc(1*sizeof(struct node));
108        temp->ptr = top;
109        temp->info = data;
110        top = temp;
111    }
112    count++;
113}
114 
115/* Display stack elements */
116void display()
117{
118    top1 = top;
119 
120    if (top1 == NULL)
121    {
122        printf("Stack is empty");
123        return;
124    }
125 
126    while (top1 != NULL)
127    {
128        printf("%d ", top1->info);
129        top1 = top1->ptr;
130    }
131 }
132 
133/* Pop Operation on stack */
134void pop()
135{
136    top1 = top;
137 
138    if (top1 == NULL)
139    {
140        printf("\n Error : Trying to pop from empty stack");
141        return;
142    }
143    else
144        top1 = top1->ptr;
145    printf("\n Popped value : %d", top->info);
146    free(top);
147    top = top1;
148    count--;
149}
150 
151/* Return top element */
152int topelement()
153{
154    return(top->info);
155}
156 
157/* Check if stack is empty or not */
158void empty()
159{
160    if (top == NULL)
161        printf("\n Stack is empty");
162    else
163        printf("\n Stack is not empty with %d elements", count);
164}
165 
166/* Destroy entire stack */
167void destroy()
168{
169    top1 = top;
170 
171    while (top1 != NULL)
172    {
173        top1 = top->ptr;
174        free(top);
175        top = top1;
176        top1 = top1->ptr;
177    }
178    free(top1);
179    top = NULL;
180 
181    printf("\n All stack elements destroyed");
182    count = 0;
183}