package com.coding.basic;
/**
* 2017/2/24
* @author 236995728
*
*/
public class Stack {
private ArrayList elementData = new ArrayList();
/**
* push进元素
* @param o
*/
public void push(Object o){
elementData.add(o);
}
/**
* pop出元素
* @return
*/
public Object pop(){
Object o = elementData.get(elementData.size()-1);
elementData.remove(elementData.size()-1);
return o;
}
/**
* 查找栈顶元素
* @return
*/
public Object peek(){
return elementData.get(elementData.size()-1);
}
/**
* 判断是否为空栈
* @return
*/
public boolean isEmpty(){
return elementData.size() == 0;
}
/**
* 栈里元素的个数
* @return
*/
public int size(){
return elementData.size();
}
}