#include<stdio.h>

struct stack
{
 int top;
 char item[10];
};

int isfull(struct stack *ps)
{
 if(ps->top==9)
   {
    return(1);
   }
 else
   {
    return(0);
   }
}

int isempty(struct stack *ps)
{
 if(ps->top==-1)
   {
    return(1);
   }
 else
   {
    return(0);
   }
}

void push(struct stack *ps,char a)
{
 ps->top++;
 ps->item[ps->top]=a;
}

void pop(struct stack *ps)
{
 ps->top--;
}

void display(struct stack *ps)
{
 int i=ps->top;
 printf("\nthe stack contains:\n");
 for(i=ps->top;i!=-1;--i)
    {
     printf("%c",ps->item[i]);
    }
}

void main()
{
 struct stack s;
 int ch,n;
 char a,b;
 s.top=-1;
 do
   {
    printf("\nenter your choice:\n1.push\n2.pop\n3.display\n4.exit");
    scanf("%d",&ch);
    switch(ch)
       {
        case 1: if(isfull(&s))
                  {
                   printf("\nstack is full");
                  }
                else
                  {
                   printf("\nenter character to be pushed:");
                   scanf("%s",&a);
                   push(&s,a);
                  }
                break;

        case 2: if(isempty(&s))
                  {
                   printf("\nstack is empty");
                  }
                else
                  {
                   pop(&s);
                  }
                break;

        case 3: if(isempty(&s))
                  {
                   printf("\nstack is empty");
                  }
                else
                  {
                   display(&s);
                  }
                break;
      }
    }
 while(ch!=4);
}