Java——写一个简单的计算器

用我目前学到Java知识写一个简单的计算器，比较简陋

package base;

import java.util.Scanner;

public class Calc02 {
    public static void main(String[] args) {
        String str;
        double m;
        Scanner scanner = new Scanner(System.in);
        String c;
        do{
            System.out.println("请输入进行的运算（+-*/）");
        str=scanner.nextLine();
            System.out.println("请输入运算的数字");
            double x=scanner.nextDouble();
            double y=scanner.nextDouble();
        switch (str){
            case "+":
                m=x+y;
                System.out.println(x+"+"+y+"="+m);
                break;
            case "-":
                m=x-y;
                System.out.println(x+"-"+y+"="+m);
                break;
            case "*":
                m=x*y;
                System.out.println(x+"*"+y+"="+m);
                break;
            case "/":
                if(y==0){
                    System.out.println("除零错误");
                }
                else {
                m=x/y;
                System.out.println(x+"/"+y+"="+m);
                }
                break;
        }
            System.out.println("是否进行下次运算（Y/N）");
            c = scanner.next();
            scanner.nextLine();
        }while (c.equals("Y")||c.equals("y"));
        scanner.close();
    }

}