stack

#include<stdio.h>
#define SIZE 5      /* Size of Stack */

char s[SIZE][20];        /* Global declarations */
int top = 0;       /* -1 indicates stack is empty */

void push(char *element) /* Function for PUSH operation */
{
    if(isFull())
        printf("\n Stack is full!\n");
    else {
        ++top;
        strcpy(s[top],element);
    }
}

char* pop()           /* Function for POP operation */
{
    char element[20];
    if(isEmpty()) {
        printf("\nStack is Empty!\n");
    }
    else {
        printf("\n Popped Element is %s \n", s[top]);
        top--;
    }
}

int isFull()       /* Function to Check if Stack is Full */
{
    if(top == SIZE)
        return 1;
    return 0;
}

int isEmpty()      /* Function to Check if Stack is Empty */
{
    if(top == 0)
        return 1;
    return 0;
}

void display()  /* Function to display status of Stack */
{
    int i;
    if(isEmpty())
        printf(" \n Empty Stack\n");
    else
    {
        for (i = top; i>=1; i--)
            printf("%s\n", s[i]);
    }
}

void main()  /* Main Program */
{
    int opn;
    char element[20];
    do
    {
        printf("\n Stack Operations \n");
        printf("\n Press 1-Push, 2-Pop,3-Display,4-Exit\n");
        printf("\n Your option ? ");
        scanf("%d", &opn);

        switch (opn)
        {
        case 1:
            printf("\n Enter the element to be pushed ?");
            scanf(" %[^\n]s", &element);
            push(element);
            break;
        case 2:
            pop();
            break;
        case 3:
            printf("\n Status of Stack \n");
            display();
            break;
        case 4:
            printf("\n Terminating \n");
            break;
        default:
            printf("\n Invalid Option !!! Try Again !! \n");
            break;
        }
        printf("\n Press a Key to Continue . . . ");
    }
    while (opn != 4);
}