package com.coding.basic;
public class Stack {
private ArrayList elementData = new ArrayList();
public void push(Object o){
elementData.add(0, o);
}
public Object pop(){
Object object = elementData.get(0);
elementData.remove(0);
return object;
}
public Object peek(){
return elementData.get(0);
}
public boolean isEmpty(){
return elementData.size()==0?true:false;
}
public int size(){
return elementData.size();
}
}