package com.github.ipk2015.coding2017.basic.stack;
import java.util.EmptyStackException;
import com.github.ipk2015.coding2017.basic.array.ArrayList;
public class Stack {
private ArrayList elementData = new ArrayList();
public void push(Object o){
elementData.add(o);
}
public Object pop(){
if(isEmpty()){
throw new EmptyStackException();
}
Object data=elementData.remove(size()-1);
return data;
}
public Object peek(){
if(isEmpty()){
throw new EmptyStackException();
}
return elementData.get(size()-1);
}
public boolean isEmpty(){
return size()==0;
}
public int size(){
return elementData.size();
}
public String toString(){
StringBuffer buffer=new StringBuffer();
int size=elementData.size();
for(int i=0;i<size;i++){
buffer.append(elementData.get(i)+",");
}
return buffer.toString();
}
}