public class ArrayStack{
    private int size;
    private int maxSize;
    private Object []data;

    public ArrayStack(){
        data=new Object[10];
        maxSize=10;
        size=0;
    }

    public ArrayStack(int _maxSize){
        data=new Object[_maxSize];
        maxSize=_maxSize;
        size=0;
    }

    public void push(Object _data){
        if(size==maxSize){
            System.out.println("Stack Over Flow");
        }
        else{
            data[size]=_data;
            size++;
        }
    }

    public void pop(){
        if(size==0){
            System.out.println("Stack Under Flow");
        }
        else{
            size--;
            data[size]=null;
        }
    }

    public Object top(){
        return data[size-1];
    }

    public boolean isEmpty(){
        return (size==0);
    }

    public boolean isFull(){
        return (size==maxSize);
    }

    public void display(){
        if(isEmpty()){
            System.out.println("(Empty)");
        }
        else{
            System.out.println("xxxxxx");
            for(int i=size-1;i>=0;i--){
                System.out.printf("|%4d",data[i]);
                System.out.println("|");
            }
            System.out.println("xxxxxx");
        }
    }
}