STACKS USING LINKED LIST

#include <stdio.h>

#include <stdlib.h>

struct node

{

    int info;

    struct node *ptr;

}*top,*top1,*temp;

int topelement();

void push(int data);

void pop();

void empty();

void display();

void destroy();

void stack_count();

void create();

int count = 0;

void main()

{

    int no, ch, e;

    printf("\n 1 - Push");

    printf("\n 2 - Pop");

    printf("\n 3 - Top");

    printf("\n 4 - Empty");

    printf("\n 5 - Dipslay");

    create();

    while (1)

    {

        printf("\n Enter choice : ");

        scanf("%d", &ch);

         switch (ch)

        {

        case 1:

            printf("Enter data : ");

            scanf("%d", &no);

            push(no);

            break;

        case 2:

            pop();

            break;

        case 3:

            if (top == NULL)

                printf("No elements in stack");

            else

            {

                e = topelement();

                printf("\n Top element : %d", e);

            }

            break;

        case 4:

            empty();

            break;

        case 5:

            display();

            break;

        default :

            printf(" Wrong choice, Please enter correct choice  ");

            break;

        }

    }

}

void create()

{

    top = NULL;

}

void push(int data)

{

    if (top == NULL)

    {

        top =(struct node *)malloc(1*sizeof(struct node));

        top->ptr = NULL;

        top->info = data;

    }

    else

    {

        temp =(struct node *)malloc(1*sizeof(struct node));

        temp->ptr = top;

        temp->info = data;

        top = temp;

    }

    count++;

}

void display()

{

    top1 = top;

    if (top1 == NULL)

    {

        printf("Stack is empty");

        return;

    }

    while (top1 != NULL)

    {

        printf("%d ", top1->info);

        top1 = top1->ptr;

    }

 }

void pop()

{

    top1 = top;

    if (top1 == NULL)

    {

        printf("\n Error : Trying to pop from empty stack");

        return;

    }

    else

        top1 = top1->ptr;

    printf("\n Popped value : %d", top->info);

    free(top);

    top = top1;

    count--;

}

int topelement()

{

    return(top->info);

}

void empty()

{

    if (top == NULL)

        printf("\n Stack is empty");

    else

        printf("\n Stack is not empty with %d elements", count);

}