package org.dul.CodingTask.homework_2017_2_25;
public class Stack {
private ArrayList elements = new ArrayList();
public void push(Object object) {
elements.add(object);
}
public Object pop() {
if (isEmpty())
return null;
else {
return elements.remove(elements.size() - 1);
}
}
public Object peek() {
if (isEmpty())
return null;
else {
return elements.get(elements.size() - 1);
}
}
public boolean isEmpty() {
if (elements.size() == 0)
return true;
else
return false;
}
public int size() {
return elements.size();
}
}