Simple Stack implementation in C

stack.c

/* program for stack implementation in c*/
#include <stdio.h>
#include <stdlib.h>
#include<conio.h>

//global variables
int stackk[20],top;

//function definition
void push(int);
int pop();

int main()
{
    int element,cont,choice,i;
    top=-1;
    cont=1;

    do
    {
        printf("\nTHE FOLLOWING CHOICES ARE AVAILIABLE : ");
        printf("\n1.PUSH AN ELEMENT");
        printf("\n2.POP AN ELEMENT");
        printf("\n3.VIEW STACK CONTENTS");
        printf("\nENTER YOUR CHOICE : ");
        scanf("%d",&choice);

        switch(choice)
        {
            case 1:
                printf("\nENTER THE ELEMENT TO BE PUSHED : ");
                scanf("%d",&element);
                push(element);
                break;

            case 2:
                element=pop();
                if(element!=99999)
                {
                    printf("\nTHE ELEMENT POPPED  IS : %d",element);
                }
                break;

            case 3:
                printf("\nTHE ELEMENTS OF STACK ARE : ");
                for(i=0;i<=top;i++)
                {
                    printf("\n%d",stackk[i]);
                }
        }
        printf("\nDO YOU WANT TO CONTINUE (1/0): ");
        scanf("%d",&cont);

    }while(cont==1);
    return 0;
}

void push(int element)
{
    //increment top value
    top++;
    
    //check if stack is full
    if(top==20)
    {
        printf("\nSTACKFULL!!!!!");
    }
    else
    {
        stackk[top]=element;
        printf("\nELEMENT PUSHED!!");
    }
    return;
}

int pop()
{
    int element;
    //check if stack is empty
    if(top<0)
    {
        printf("\nSTACKEMPTY!!!!!");
        //consider all elements are smaller than 99999
        return 99999;       //returning  99999 to indicate stackempty 
    }
    else
    {
        element=stackk[top];
        top--;
        return element;
    }
}