数组实现stack

package stack;

import java.util.EmptyStackException;


public class MyStack<E> {
    //Stack 的数组实现
    private int CAPACITY;
    private Object[] theArray;
    private int topOfStack;

    public MyStack() {
        CAPACITY = 100;
        topOfStack = -1;
        theArray = new Object[CAPACITY];
    }


    public MyStack(int cAPACITY) {
        CAPACITY = cAPACITY;
        topOfStack = -1;
        theArray = new Object[CAPACITY];
    }

    public boolean empty() {
        return topOfStack == -1;
    }

    public Object peak() {
        if (this.empty())
            throw new EmptyStackException();
        return theArray[topOfStack];
    }

    public int size() {
        return topOfStack+1;
    }

    public void push(E value) {
        theArray[++topOfStack] = value;
    }

    public Object pop() {
        if (topOfStack != -1) {
            return theArray[topOfStack--];
        }
        return null;
    }

}