Pop and push

#include <stdio.h>
#include <stdlib.h>
#include<Conio.h>
#define max 10
struct stack
{
int top;
int item[max];

}s;

void push();
void pop();
void display();
void main()
{
      system("cls");
      s.top=-1;

      int choice;
      while (1)
      {

            printf("Enter your choice");

            printf("\n1.Push\n 2. Pop\n 3.Display \n4.Exit\n");
    scanf("%d",&choice);

            switch (choice)
            {
                  case 1:push();
                  break;
                  case 2:pop();
                  break;
                  case 3:display();
                  break;
                  case 4:
                  exit(0);
                  default: printf("Enter number in range: \n");
            }
      }
}
      void push()
      {

int val;
      if (s.top==max-1)
      printf("Overflow:");
      else
      {
        printf("Enter the element you want to push: \n");
        scanf("%d",&val) ;
        s.top=s.top+1;
        s.item[s.top]=val;
      }




        }
        void pop()
        {

           if (s.top==-1)
           {
                 printf("Empty stack");
           }
           else
           {
                 printf("Deleted stack is %d\n",s.item[s.top]);
                 s.top=s.top-1;
           }

        }
        void display()
        {
                system("cls");
              int i;
              if (s.top==-1)
              {
                    printf("Empty\n");

              }
              else
              {
                    for (i=s.top;i>=0;--i)
                    {
                        printf("Stack:\%d \n",s.item[i]);

                    }
              }

        }