为什么在calAverage方法中return语句不返回任何东西

Question

So, I have coded everything, but return statement isn't returning or printing out anything in the output. The return statement is in my calAverage method. And the output should look like this https://gyazo.com/328bcfebfb08709edbc0e62a93ada7f8 but I have everything but the calAverage output. I don't get what I did wrong. I know I have to call the method like this: sc.calAverage(a, b, c); and then assign the return value to a variable and the print it out but I don't know how to do it with the calAverage method since it has three arguments.

import java.util.Scanner;
public class SecretCode
{
    //no instance variables
    public SecretCode(){
    }
    
    public double calAverage(int a, int b, int c){
        double average = 0.0;
        //your work - step 2
        
        average = (a + b + c) / 3.0;
        return average;
    }
    public void decodeMe(String s1){
        //your work here step 4
        //This method will take in a String and then process the string to produce output withe the following rules:
        // The first 5 characters are needed but must be uppercase()
        // The first integer will decrease by 121
        // The last number only takes the last 2 decimals
        // Print out 3 lines of data as followed:
        // XXXXX
        // XXX
        // XX
        
        String s = "Delta 230 ATA 23.75";
        s1 = s.substring(0, 5);
        String s2 = s1.toUpperCase();
        
        int wholeNumber = Integer.parseInt(s.substring(6, 9));
        int finalNumber = wholeNumber - 121; 
        
        int lastNumber = Integer.parseInt(s.substring(17,19));
        
        
        System.out.println(s2 + "\n" + finalNumber + "\n" + lastNumber);
        

    }
       
    public static void main(String args[]){
        int a, b, c;
        String s;
        SecretCode sc = new SecretCode();
        Scanner myObj = new Scanner(System.in);
        System.out.println("Enter 3 numbers separated by space ");
        //your work step 3
        // receive 3 integer values and call calAverage() method 
        // print out the average 
        
        a = myObj.nextInt();
        b = myObj.nextInt();
        c = myObj.nextInt();
        sc.calAverage(a, b, c);
        
       
        
        
        //
        Scanner myObj1 = new Scanner(System.in);
        System.out.println("Enter a secret code below ");
        //Step enter the code: Delta 230 ATA 23.75
        s = myObj1.nextLine();
        sc.decodeMe(s);
        //
    }
}

Answer 1

将函数的响应保存在变量中：

double averageValue = sc.calcAverage(5, 3, 2);

Answer 2

You should change

sc.calAverage(a, b, c)

to

double avg = sc.calAverage(a, b, c)
System.out.println(avg);

in your main method if you want to print the value returned by the calAverage method.

Or print the average after calculating it in the method calAverage .

public double calAverage(int a, int b, int c) {
        double average = 0.0;
        //your work - step 2

        average = (a + b + c) / 3.0;
        System.out.println(average);
        return average;
    }