java - Java 中返回/传递变量

Question

我是一名初级程序员，我们被分配将方法实现为代码。我的这个年级平均代码工作得很好，但是一旦我把它分解成方法，我就无法让返回函数工作。我尝试过移动括号并重新排列代码，但无济于事。我相信这可能与我的变量范围有关...提前致谢:)

package milsteadgrades;
import java.util.Scanner;

public class MilsteadGrades {


public static void main(String[] args)

{
//Call methods to execute program.
displayInfo();
double numOfgrades = getInput();
double average = getAverage(numOfgrades);
char letgrade = determineLetterGrade(average);
displayGrades(average, letgrade);
}


public static void displayInfo()

{
System.out.println("Mallory Milstead");
System.out.println("This program will prompt the user for a number of 
grades"
+ " and each grade. Then the program calculates and displays the average and 
letter"+" grade.");
}

 public static double getInput()

{
//Prompt user to enter number of grades and assign that number to 
numOfgrades.
System.out.print("How many grades would you like to average? ");
Scanner keyboard = new Scanner(System.in);
double numOfgrades = keyboard.nextDouble();
return numOfgrades;
}

public static double getAverage(numOfgrades)

{
//Prompt the user to enter grades.
System.out.println("Enter exam scores : ");
Scanner keyboard = new Scanner(System.in);
double total = 0;
for (double i = 0; i < numOfgrades; i++) {
double grade = keyboard.nextDouble();
total+=grade;}
double average = total/numOfgrades;
return average;
}

public static char determineLetterGrade(average)

{ double testscore = average;
    char letgrade;

    if (testscore >= 90) 
    {
        letgrade = 'A';
    } else if (testscore >= 80) 
    {
        letgrade = 'B';
    } else if (testscore >= 70) 
    {
        letgrade = 'C';
    } else if (testscore >= 60) 
    {
        letgrade = 'D';
    } else 
    {
        letgrade = 'F';
    }
    return letgrade;
    }

public static void displayGrades(average, letgrade)

{
System.out.println("The average of the grades is "+average+ " and the 
letter grade"+ " is " + letgrade+".");}

}

从 -public static double getAverage(numOfgrades)- 行开始，我不断收到“找不到符号”错误消息。我的变量都没有被识别。

Answer 1

您需要声明getAverage的参数类型。喜欢

public static double getAverage(double numOfgrades)

对于其他方法(不是模块)也是如此。阅读this或this获取提示。