java,循环，switch写简易计算器

public class LianXIDemo03 {
    public static void main(String[] args) {
        //计算机器
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入1234，加减乘除");

        double num1,num2,num3;
        boolean s = true;
        num1 = 0;
        num2 = 0;
        num3 = 0;
        while(s){
            int i = scanner.nextInt();
            switch(i){

                case 1:
                    System.out.println("输入第一个加法数字");
                    num1 = scanner.nextDouble();
                    System.out.println("第二个");
                    num2 = scanner.nextDouble();
                    num3=num1+num2;
                    System.out.println(num3);
                    break;
                case 2:
                    System.out.println("输入第一个减法数字");
                    num1 = scanner.nextDouble();
                    System.out.println("第二个");
                    num2 = scanner.nextDouble();
                    num3=num1-num2;
                    System.out.println(num3);
                    break;
                case 3:
                    System.out.println("输入第一个乘法数字");
                    num1 = scanner.nextDouble();
                    System.out.println("第二个");
                    num2 = scanner.nextDouble();
                    num3=num1*num2;
                    System.out.println(num3);
                    break;
                case 4:
                    System.out.println("输入第一个除法数字");
                    num1 = scanner.nextDouble();
                    System.out.println("第二个");
                    num2 = scanner.nextDouble();
                    num3=num1/num2;
                    break;
                default:
                    System.out.println("输入错误");
                    break;






            }


        }
        scanner.close();


    }
}