Stack (Array Based)

import java.util.*;
class Stack
{
    int arr[];
    int size, top;
    Stack(int s)
    {
        size=s;
        top=-1;
        arr=new int[size];
    }
    void push(int e)
    {
        if(top==size-1)
        System.out.println("Stack Overflow");
        else
        arr[++top]=e;
    }
    int pop()
    {
        if(top==-1)
        return -9999;
        else
        return arr[top--];
    }
    void show()
    {
        if(top==-1)
        System.out.println("Empty Stack");
        else
        {
            System.out.println("The elements in the stack:");
            for(int i=top;i>=0;i--)
            System.out.println(arr[i]);
        }
    }
    public static void main()
    {
        Scanner in=new Scanner(System.in);
        System.out.println("Enter size");
        int s=in.nextInt();
        int ch,e,d,c;
        Stack obj=new Stack(s);
        do
        {
            System.out.println("\f1. Push");
            System.out.println("2. Pop");
            System.out.println("3. Display");
            System.out.println("4. Quit");
            System.out.println("Enter choice");
            ch=in.nextInt();
            switch(ch)
            {
                case 1:
                System.out.println("Enter a number");
                e=in.nextInt();
                obj.push(e);
                break;
                
                case 2:
                d=obj.pop();
                if(d==-9999)
                System.out.println("Stack Underflow");
                else
                System.out.println("Deleted : "+d);
                break;
                
                case 3:
                obj.show();
                break;
                
                case 4:
                System.exit(0);
                default: System.out.println("Wrong choice");
            }
            System.out.println("Enter 1 to continue...");
            c=in.nextInt();
        }
        while(c==1);
    }
}