写一个计算机，要求实现加减乘除功能，并且能够循环接收新数据，通过用户交互实现

代码思路：

1.写4个方法：加减乘除；每个方法输入两个数据，并传出操作结果。

2.main()中利用for循环和switch进行用户交互，并退出循环。

import java.util.Scanner;

public class calculation {
    public static void main(String[] args) {
        System.out.println("==========简单计算机===========");
        System.out.println("1.加法\t" + "2.减法\t" + "3.乘法\t" + "4.除法\t" + "5.退出");
        Scanner scanner = new Scanner(System.in);

        for ( ; ; ){
            System.out.println("请输入您想要进行的操作：");
            int s =scanner.nextInt();

            switch (s){
                case 1:
                    add();
                    break;
                case 2:
                    reduce();
                    break;
                case 3:
                    ride();
                    break;
                case 4:
                    divide();
                    break;
                case 5:
                    break;
                default:
                    System.out.println("输入的操作符号有误！");
                    System.out.println();
            }

            if (s==5){
                scanner.close();
                System.out.println("退出循环！");
                break;
            }
        }
    }

    public static void add(){
        Scanner scanner2 = new Scanner(System.in);
        System.out.println("输入第一个数x：");
        double x = scanner2.nextDouble();
        System.out.println("输入第二个数y：");
        double y = scanner2.nextDouble();
        System.out.println("================================");
        System.out.println("x + y = "+(x+y)+"\n");
    }
    public static void reduce(){
        Scanner scanner2 = new Scanner(System.in);
        System.out.println("输入第一个数x：");
        double x = scanner2.nextDouble();
        System.out.println("输入第二个数y：");
        double y = scanner2.nextDouble();
        System.out.println("================================");
        System.out.println("x - y = "+(x-y)+"\n");
    }
    public static void ride(){
        Scanner scanner2 = new Scanner(System.in);
        System.out.println("输入第一个数x：");
        double x = scanner2.nextDouble();
        System.out.println("输入第二个数y：");
        double y = scanner2.nextDouble();
        System.out.println("================================");
        System.out.println("x * y = "+(x*y)+"\n");
    }
    public static void divide(){
        Scanner scanner2 = new Scanner(System.in);
        System.out.println("输入第一个数x：");
        double x = scanner2.nextDouble();
        System.out.println("输入第二个数y：");
        double y = scanner2.nextDouble();
        System.out.println("================================");
        if (y==0){
            System.out.println("除数不能为0！"+"\n");
        }else {
            System.out.println("x / y = "+(x/y)+"\n");
        }
    }
}