Program:

/*Stack Using Array*/

#include<stdio.h>

#include<conio.h>

#define MAX 10

struct stack

{

int a[MAX];

int top;

}s1;

void main()

{

int r,ch;

clrscr();

s1.top=-1;

while(1)

{

printf("\nEnter\n1-Push\n2-Pop\n3-Stacktop\n4-Display\n5-Exit\n");

scanf("%d",&ch);

switch(ch)

{

case 1:

            printf("Enter a element\t");

            scanf("%d",&r);

            push(&s1,r);

            break;

case 2:

            r=pop(&s1);

            printf("The top = %d\n",r);

            break;

case 3:

            r=stacktop(&s1);

            printf("The top = %d\n",r);

            break;

case 4:

            display(s1);

            break;

default:

            printf("~~~Exit~~~");

            getch();

            exit(0);

}

}

}

push(struct stack *m,int elt)

{

            if(m->top==MAX)

            {

                        printf("\nStack is full");

                        getch();

                        exit(0);

            }

            m->top++;

            m->a[m->top]=elt;

}

int pop(struct stack *n)

{

            int x;

            if(n->top==-1)

            {

                        printf("\nStack is empty");

                        getch();

                        exit(0);

            }

x=n->a[n->top];

n->top--;

return(x);

}

int stacktop(struct stack *o)

{

            if(o->top==-1)

            {

            printf("\nStack is empty");

            getch();

            exit(0);

            }

return(o->a[o->top]);

}

display(struct stack q)

{

            int i;

            if(q.top==-1)

            {

                        printf("\nstack is empty");

                        getch();

                        exit(0);

            }

            for(i=q.top;i>=0;i--)

            {

                        printf(" %d -> %d\n",i,q.a[i]);

            }

}

OUTPUT:

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

1

Enter a element 10

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

1

Enter a element 20

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

3

The top = 20

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

4

 1 -> 20

 0 -> 10

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

2

The top = 20

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

4

 0 -> 10

 

Enter:

1-Push 2-Pop 3-Stacktop 4-Display 5-Exit

5

~~~Exit~~~