Implentation of stack using arrays

Program:

#include<stdio.h>
#include<conio.h>
#define SIZE 10
int arr[SIZE], top = -1, i;
void push();
void pop();
void display();
void main()
{
    int ch;
    clrscr();
    do
    {
        printf("\n[1].PUSH [2].POP [3].Display [4].Exit\n");
        printf("\nEnter your choice [1-4] : ");
        scanf("%d", &ch);
        switch(ch)
        {
            case 1 :
            push();
            break;
            case 2 :
            pop();
            break;
            case 3 :
            display();
            break;
            case 4 :
            break;
            default :
            printf("\nInvalid option\n");
            getch() ;
        }
    } while(ch != 4);
    getch();
}
void push()
{
    if(top == SIZE - 1)
    {
        printf("\nStack is full (overflow)\n");
        getch();
        return;
    }
    top;
    printf("\nEnter the element to PUSH : ");
    scanf("%d", &arr[top]);
}
void pop()
{
    if(top == -1)
    {
        printf("\nStack is empty (underflow)\n");
        getch();
        return;
    }
    printf("\nThe POP element is : %d\n", arr[top]);
    getch();
    top--;
}
void display()
{
    if(top == -1)
    {
        printf("\nStack is empty (underflow)\n");
        getch();
        return;
    }
    printf("\nThe elements in stack are :\n\nTOP");
    for(i = top; i >= 0; i--)
    printf(" -> %d", arr[i]);
    printf("\n");
    getch();
}

Output:

[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 1
Enter the element to PUSH : 10
A.120 Programs in C
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 1
Enter the element to PUSH : 20
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 3
The elements in stack are :
TOP -> 20 -> 10
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 2
The POP element is : 20
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 3
The elements in stack are :
TOP -> 10
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 2
The POP element is : 10
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 2
Stack is empty (underflow)
[1].PUSH [2].POP [3].Display [4].Exit
Enter your choice [1-4] : 4