用java写一个计算机

public class Demo07 {
    public static void main(String[] args) {
        //用scanner创建一个扫描器对象，用于接收键盘数据
        Scanner scanner = new Scanner(System.in);//System.in是输入的意思
        System.out.println("请输入第1个操作数");
        int x=scanner.nextInt();
        System.out.println("请输入第2个操作数");
        int y=scanner.nextInt();
        System.out.println("请输入操作符：");
        String op=scanner.next();//从键盘接收一个字符串
        switch (op){
            case "+":
                System.out.println(x+"+"+y+"="+(x+y));//10+20=30
                break;
            case "-":
                System.out.println(x+"-"+y+"="+(x-y));
                break;
            case "*":
                System.out.println(x+"*"+y+"="+(x*y));
                break;
            case "/":
                if (y!=0){
                    System.out.println(x+"/"+y+"="+(x/y));
                }else{
                   System.out.println("除数不能为0");
                }
                break;
            default:
                System.out.println("操作符错误");
        }
    }
}