数组实现栈的结构（java）

自定义数组实现栈的结构。

package test;

public class MyArrayStackClient {
    public static void main(String[] args) {
        ArrayStack<Integer> stack = new ArrayStack<Integer>();
        // ArrayStack<Integer> stack=new ArrayStack<Integer>();
        // 入栈
        stack.push(6);
        stack.push(5);
        stack.push(4);
        stack.push(3);
        stack.push(2);
        stack.push(1);

        System.out.println("此时栈是否为空：" + stack.isEmpty());// 判断栈是否为空
        System.out.println("获取栈顶元素：    " + stack.peek());// 获取栈顶元素
        System.out.println("当前栈内元素共有：    " + stack.size() + "个");
        System.out.println("元素：    " + stack.pop() + "出栈");// 元素出栈
        System.out.println("当前栈内元素共有：    " + stack.size() + "个");
        stack.clear();
        System.out.println("当前栈内元素共有：    " + stack.size() + "个");

    }
}

package test;

public class ArrayStack<T> implements IStack<T> {
    private final int DEFAULT_SIZE = 3;
    private int size = 0;
    private int capacity = 0;

    // top指向下一个能够添加元素的位置
    private int top = 0;
    private Object[] array;

    public ArrayStack() {
        this.capacity = this.DEFAULT_SIZE;
        this.array = new Object[this.capacity];// 初始栈
        this.size = 0;
    }

    public ArrayStack(int capacity) {
        this.capacity = capacity;
        this.array = new Object[this.capacity];
        this.size = 0;
    }

    // 栈中元素为空
    @Override
    public boolean isEmpty() {
        // TODO Auto-generated method stub
        return size == 0;
    }

    // 获取栈顶元素
    @Override
    public T peek() {
        // TODO Auto-generated method stub
        return (T) this.array[this.top - 1];
    }

    @Override
    public T pop() {
        // TODO Auto-generated method stub
        T element = (T) this.array[top - 1];
        this.array[top - 1] = null;
        this.size--;
        return element;
    }

    // 元素入栈
    @Override
    public void push(T element) {
        // TODO Auto-generated method stub
        if (this.size < this.capacity) {
            this.array[top] = element;
            this.top++;
            this.size++;
        } else {
            // System.out.println("out of array");
            enlarge(); // 扩大栈的容量
            push(element);
        }
    }

    // 扩大栈的容量
    public void enlarge() {
        this.capacity = this.capacity + this.DEFAULT_SIZE;
        Object[] newArray = new Object[this.capacity];
        // System.arraycopy(array, 0, newArray, 0, array.length);
        arrayCopy(array, newArray);
        fillArray(array, null); // 用null将array填满
        this.array = newArray;
    }

    // 复制元素
    public void arrayCopy(Object[] array, Object[] newArray) {
        for (int i = 0; i < array.length; i++) {
            newArray[i] = array[i];
        }
    }

    // 向数组中装填元素
    public void fillArray(Object[] array, Object val) {
        for (int i = 0; i < array.length; i++) {
            array[i] = val;
        }
    }

    // 求出此时栈中元素的大小
    public int size() {
        return this.size;
    }

    // 清空栈
    @Override
    public void clear() {
        // TODO Auto-generated method stub
        fillArray(array, null);
        this.top = 0;
        this.size = 0;
        this.capacity = this.DEFAULT_SIZE;
        this.array = new Object[this.capacity];
    }
}

package test;

public interface IStack<T> {
    // 元素出栈，并返回出栈元素
    public T pop();

    // 元素入栈
    public void push(T element);

    // 获取栈顶元素
    public T peek();

    // 判断栈是否为空
    public boolean isEmpty();

    // 清栈
    public void clear();
}

输出结果如下：

此时栈是否为空：false
获取栈顶元素：    1
当前栈内元素共有：    6个
元素：    1出栈
当前栈内元素共有：    5个
当前栈内元素共有：    0个