java实现基于数组的栈和队列

栈和队列是非常基础但又十分重要十分常用的数据结构。栈的先入后出和队列的先入先入特性在软件工程中的应用非常广泛。以下为java版基于数组的简单实现。

/**
 * desc : 栈的数组实现
 * Created by tiantian on 2018/9/1
 */
public class Stack {

    private Object[] value;
    private int top = -1;
    private int size;

    public Stack(int size) {
        value = new Object[size];
        this.size = size;
    }

    public boolean isEmpty() {
        return top == 0;
    }

    public void push(Object val) {
        if (top == size) {
            throw new StackOverflowError();
        }

        value[++top] = val;
    }

    public Object pop() {
        if (top < 0) {
            throw new EmptyStackException();
        }

        Object obj = value[top];
        top--;
        return obj;
    }
}

/**
 * desc : 队列的数组实现
 * Created by tiantian on 2018/9/1
 */
public class Queue {
    private Object[] queue;
    private int length;
    private int head = 0;
    private int tail = 0;

    public Queue(int len) {
        this.length = len;
        queue = new Object[len];
    }

    public void enQueue(Object obj) {
        if (tail == length) {
            tail = 0;
        }
        queue[tail++] = obj;
    }

    public Object deQueue() {
        if (queue[head] == null) {
            return null;
        }

        Object temp = queue[head];
        if (head == length) {
            head = 0;
        } else {
            head++;
        }

        return temp;
    }
}