public class HelloWord {
    public static void main(String[] args){
        //用scanner接收輸入資訊
        Scanner scanner = new Scanner(System.in);
        //接收多個資訊 每一個以回車結束 
        System.out.println("輸入第一個引數a");
        double a = scanner.nextDouble();
        System.out.println("輸入運算子");
        String oper = scanner.next();
        System.out.println("輸入第二個引數b");
        double b = scanner.nextDouble();
        //宣告類物件 用來呼叫方法
        HelloWord helloWord = new HelloWord();
        //通過運算子判斷加減乘除
        switch(oper){
            case "+":
                System.out.println("加法"+helloWord.add(a,b));
                //不要忘了break 否則順序執行
                break;
            case "-":
                System.out.println("減法"+helloWord.sub(a,b));
                break;
            case "*":
                System.out.println("乘法"+helloWord.mult(a,b));
                break;
            case "/":
                System.out.println("除法"+helloWord.div(a,b));
                break;
        }




        }
//宣告加減乘除的方法
    public static double add(double a,double b){
        return a + b;
    }
    public static double sub(double a,double b){
        return a - b;
    }
    public static double mult(double a,double b){
        return a * b;
    }
    public static double div(double a,double b){
        return a/b;
    }

}