package com.coding.DataStructure;
import java.util.NoSuchElementException;
public class Stack {
private ArrayList elementData = new ArrayList();
private int size;
public void push(Object o){
elementData.add(o);
size++;
}
public Object pop(){
if(size<=0){
throw new NoSuchElementException();
}
int len = size-1;
Object val = elementData.remove(len);
size--;
return val;
}
public Object peek(){
if(size<=0){
throw new NoSuchElementException();
}
int len = size-1;
return elementData.get(len);
}
public boolean isEmpty(){
boolean flag = false;
if(size >= 0){
flag = true;
}
return flag;
}
public int size(){
return size;
}
}