IMPLEMENT STACK OPERATIONS USING STACK

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#define size 5
/* stack structure*/
struct stack  {
          int s[size];
          int top;
           }st;
//-------------------------------------
int stfull()
{
 if(st.top>=size-1)
    return 1;
 else
    return 0;
}
//-------------------------------------
void push(int item)
{
 st.top++;
 st.s[st.top] =item;
}
//-------------------------------------
int stempty()
{
 if(st.top==-1)
    return 1;
 else
    return 0;
}
//-------------------------------------
int pop()
 {
 int item;
 item=st.s[st.top];
 st.top--;
 return(item);
 }
//-------------------------------------
void display()
{
 int i;
 if(stempty())
    printf("n Stack Is Empty!");
 else
  {
  for(i=st.top;i>=0;i--)
     printf("n%d",st.s[i]);
  }
}
//-------------------------------------
void main(void)
{
int item,choice;
char ans;
st.top=-1;
clrscr();
printf("ntt Implementation Of Stack");
do
{
 printf("n Main Menu");
 printf("n1.Pushn2.Popn3.Displayn4.exit");
 printf("n Enter Your Choice");
 scanf("%d",&choice);
 switch(choice)
 {
  case 1:
        printf("n Enter The item to be pushed");
        scanf("%d",&item);
        if(stfull())
            printf("n Stack is Full!");
        else
            push(item);
        break;
  case 2:
        if(stempty())
            printf("n Empty stack!Underflow !!");
        else
          {
          item=pop();
          printf("n The popped element is %d",item);
          }
        break;
  case 3:
        display();
        break;
  case 4:
        exit(0);
 }
 printf("n Do You want To Continue?");
 ans=getche();
}while(ans =='Y'||ans =='y');
getch();
}