Java编写简易计算器

public static void main(String[] args) {
    method();
    while (true){
        Scanner scanner = new Scanner(System.in);
        System.out.println("退出输入Q，继续使用输入Y");
        String str = scanner.nextLine();
        if(str.equals("Y")){
            method();
        }else if(str.equals("Q")){
            System.out.println("程序结束！");
            System.exit(0);
            scanner.close();
        } else {
            System.out.println("输入错误！请重新输入！");
        }
    }
}
    public static void method(){
    Scanner scanner = new Scanner(System.in);
    System.out.println("请输入第一个数字：");
    float nmb1 = scanner.nextFloat();
    System.out.println("支持的运算符：+、-、*、/、^);
    System.out.println("请输入运算符：");
    String operator  = scanner.next();
    System.out.println("请输入第二个数字：");
    float nmb2 = scanner.nextFloat();
    switch (operator ) {
        case "+":
            add(nmb1, nmb2);
            break;
        case "-":
            subtract(nmb1, nmb2);
            break;
        case "*":
            multiply(nmb1, nmb2);
            break;
        case "/":
            divide(nmb1, nmb2);
            break;
        case "^":
            power(nmb1,nmb2);
            break;
        default:
            System.out.println("*****输入错误*****");
    }
}
    public static void add ( float a, float b){
        System.out.println(a + b);
    }
    public static void subtract ( float a, float b){
        System.out.println(a - b);
    }
    public static void multiply ( float a, float b){
        System.out.println(a * b);
    }
    public static void divide ( float a, float b) {
        if (b == 0) {
            System.out.println("除数不能为0");
        } else {
            System.out.println(a / b);
        }
   	 }
    public static void power(float a,float b){
        double end = Math.pow(a,b);
        System.out.println(end);
   	 }
    }