栈-用单链表实现

话不多说，直接上代码~

package datastructres.stack;

import java.util.Scanner;

/**
 * @author ：Yan Guang
 * @date ：Created in 2021/1/10 11:45
 * @description：
 */
public class LinkListStackDemo {
    public static void main(String[] args) {
        LinkListStack stack = new LinkListStack(4);
        Scanner scanner = new Scanner(System.in);
        int key = 0;
        boolean loop = true;

        while (loop) {
            System.out.println("1show表示展示栈");
            System.out.println("2push表示入栈");
            System.out.println("3pop表示出栈");
            System.out.println("4exit表示退出程序");
            System.out.println("请输入你的选择");
            key = scanner.nextInt();
            switch (key) {
                case 1:
                    stack.showStack();
                    break;
                case 2:
                    System.out.println("请输入一个数字");
                    int value = scanner.nextInt();
                    stack.push(value);
                    break;
                case 3:
                    try {
                        int res = stack.pop();
                        System.out.printf("出栈的数据是%d\n", res);
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 4:
                    scanner.close();
                    loop=false;
                    break;
            }
        }
        System.out.println("程序退出~");
    }
}

class LinkListStack{
    private HeroNode2 head = new HeroNode2(-1);
    private int maxSize;
    private HeroNode2 top=head;

    public LinkListStack(int maxSize) {
        this.maxSize = maxSize;
    }

    public boolean isFull() {
        return top.getNo()==maxSize-1;
    }

    public boolean isEmpty() {
        return head.next==null;
    }

    public void push(int value) {
        if (isFull()) {
            System.out.println("栈满，无法添加~");
            return;
        }
        HeroNode2 node = new HeroNode2(value);
        if (head.getNext()==null){
            head.setNext(node);
        }else {
            top.setNext(node);
        }
        top = top.getNext();
    }

    public int pop() {
        if (isEmpty()) {
            //throw相当于已经停止了代码，所以不用return
            //当存在返回值的时候(不为void)的时候，我们尽量可以抛出一个异常来代替return
            throw new RuntimeException("栈空，无法取出数据~");
        }
        int value =top.getNo();
        top.setNo(value-1);
        return value;
    }

    public void showStack() {
        if (isEmpty()) {
            System.out.println("栈已空~");
            return;
        }
        //循环的时候是从栈顶往下循环，也就是从数组的最后开始循环的~
        for (int i = top.getNo(); i >= 0; i--) {
            System.out.printf("stack[%d]=%d\n", i, i);
        }
    }
}

class HeroNode2 {
    public int no;
    public HeroNode2 next;

    public HeroNode2(int no) {
        this.no = no;
    }

    public int getNo() {
        return no;
    }

    public HeroNode2 getNext() {
        return next;
    }

    public void setNext(HeroNode2 next) {
        this.next = next;
    }

    public void setNo(int no) {
        this.no = no;
    }

    @Override
    public String toString() {
        return "heroNode{" +
                "no=" + no;
    }
}

这里不足的地方就是我在出栈的时候偷鸡了一下，没有移动指针，而是直接将序列号赋值-1，实际上应该是要用双链表来比较好实现，或者用两个指针的单链表，但是这里只是简单演示一下，所以就没有写那么麻烦了，欢迎大家讨论~