import java.util.Scanner;
//實現兩個數之間的四則運算
public class Demo03 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);  //將scanner物件匯入
        double result = 0;
        
        //分別輸入計算的數字和符號
        System.out.print("請輸入第一個數字");
        double num1 = scanner.nextDouble();

        System.out.print(
 
"請輸入運算字元");
        String operate = scanner.next();

        System.out.print("請輸入第二個數字");
        double num2 = scanner.nextDouble();

        //switch語句來判斷計算符號
        switch (operate){
            case "+" :
                result = add(num1,num2);
                break;

            case "-" :
                result 
 
= sub(num1,num2);
                break;

            case "*" :
                result = mult(num1,num2);
                break;
            case "/" :
                result = div(num1,num2);
                break;
        }
        System.out.println(result);
    }


    //定義加、減、乘、除四個方法
    public static
 
 double add(double num1, double num2){
        return  num1 +num2;
    }

    public static double sub(double num1, double num2){
        return num1-num2;
    }

    public static double mult(double num1, double num2){
        return num1*num2;
    }

    public static double div(double num1, double num2){
        return num1/num2;
    }
}