package com.coding.basic;
public class Stack {
private ArrayList elementData = new ArrayList();
public void push(Object o){
for (int i = 0; i < elementData.size(); i++) {
if(elementData.get(i)==null){
elementData.add(i, o);
}
}
}
public Object pop(){
int length = elementData.size();
elementData.remove(length-1);
return elementData.get(length-1);
}
public Object peek(){
int length = elementData.size();
return elementData.get(length-1);
}
public boolean isEmpty(){
if(elementData.size()==0){
return true;
}else{
return false;
}
}
public int size(){
return elementData.size();
}
}