为什么在 calAverage 方法中 return 语句不返回任何内容

Question

所以，我已经编写了所有代码，但是 return 语句没有返回或打印输出中的任何内容。 return 语句在我的 calAverage 方法中。输出应该看起来像这样https://gyazo.com/328bcfebfb08709edbc0e62a93ada7f8，但除了 calAverage 输出之外，我什么都有。我不明白我做错了什么。我知道我必须调用这样的方法： sc.calAverage(a, b, c);然后将返回值分配给一个变量并将其打印出来，但我不知道如何使用 calAverage 方法来执行此操作，因为它具有三个参数。

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

你应该改变

sc.calAverage(a, b, c)

到

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

如果您想打印calAverage 方法返回的值，请在您的 main 方法中。

或者在方法calAverage计算后打印平均值。

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;
    }

Answer 2

将函数的响应保存在一个变量中：

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