package data2_19;
import java.util.EmptyStackException;
public class Stack {
private ArrayList elementData;
private int elementCount;
public Stack() {
this.elementData = new ArrayList();
this.elementCount = 0;
}
public void push(Object o){
elementData.add(o);
elementCount++;
}
public Object pop(){
Object object = elementData.remove(elementCount-1);
elementCount--;
return object;
}
public Object peek(){
if(isEmpty()){
throw new EmptyStackException();
}
return elementData.get(elementCount-1);
}
public boolean isEmpty(){
return elementCount==0;
}
public int size(){
return elementCount;
}
public static void main(String[] args) {
Stack stack = new Stack();
stack.push(1);
stack.push(2);
System.out.println(stack.pop());
System.out.println(stack.peek());
}
}