package com.coding.basic;
import java.util.EmptyStackException;
public class Stack {
private ArrayList elementData = new ArrayList();
@Override
public String toString() {
return elementData+"";
}
private void emptyStack() {
if (elementData.size() == 0)
throw new EmptyStackException();
}
public void push(Object o) {
elementData.add(o);
}
public Object pop() {
emptyStack();
return elementData.remove(elementData.size() - 1);
}
public Object peek() {
emptyStack();
return elementData.get(elementData.size() - 1);
}
public boolean isEmpty() {
return elementData.size() == 0 ? true : false;
}
public int size() {
return elementData.size();
}
}