Question

尝试编写成绩计算器程序，并且遇到将返回变量从一种方法传递到另一种方法的问题。我是编码的新手，所以我确定这不是很漂亮，但是希望能得到一些帮助。我有一种计算作业分数的方法，一种计算期中分数的方法以及一种计算最终分数的方法。我正在尝试在最后一个方法中调用返回变量以计算总体成绩。该错误是在调用CourseScore方法时显示的：GradeCalc类型的courseScore（int，int，int）方法不适用于参数（）。任何帮助表示赞赏！

import java.util.*;
public class GradeCalc {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int overAll;
        int midtermScore;
        int finalsScore;
        hwpoints();
        midTerm();
        courseScore();  

}

        public static int hwpoints() {
            int x;
            int hwTotal = 0;
            int pointsPossible = 0;
            Scanner input = new Scanner(System.in);
            System.out.println("Enter number of assignments:");
            x = input.nextInt();
                for(int i = 1; i <= x; i++) {
                    System.out.println("Enter assignment score:");
                    int hwScore = input.nextInt();
                    hwTotal += hwScore;
                    System.out.println("Enter total possible points:");
                    int points = input.nextInt();
                            pointsPossible += points;
                        }
                int overAll = (hwTotal / x);
                System.out.println("You got " + hwTotal + " out of " + pointsPossible + ". Your overall Homework grade is a: " + overAll);
                return overAll;
        }
        public static int midTerm() {
            int midtermPoints;
            int midtermPossible;
            int midtermScore;
            Scanner input = new Scanner(System.in);
            System.out.println("Enter Midterm Score:");
            midtermPoints = input.nextInt();
            System.out.println("Enter total possible Midterm Points:");
            midtermPossible = input.nextInt();
            midtermScore = (midtermPoints / midtermPossible);
            System.out.println("Your Midterm score is " + midtermScore);
            return midtermScore;

        }
        public static int finalScore() {
            int finalsPoints;
            int finalsPossible;
            int finalsScore;
            Scanner input = new Scanner(System.in);
            System.out.println("Enter Finals Score:");
            finalsPoints = input.nextInt();
            System.out.println("Enter total possible Finals Points:");
            finalsPossible = input.nextInt();
            finalsScore = (finalsPoints / finalsPossible);
            System.out.println("Your Finals score is " + finalsScore);
            return finalsScore;
    }
        public static void courseScore(int finalsScore, int midtermScore, int overAll) {
            Scanner input = new Scanner(System.in);
            System.out.println("What percent of your grade is the final?");
            int testWeight = input.nextInt();
            System.out.println("What percent of your grade is the midterm?");
            int midtermWeight = input.nextInt();
            System.out.println("What percent of your grade is the homework?");
            int hwWeight = input.nextInt();

            int testWeighted = (finalsScore * (testWeight / 100));
            int midtermWeighted = (midtermScore * (midtermWeight / 100));
            int hwWeighted = (overAll * (hwWeight / 100));
            int courseScore = ((hwWeighted + midtermWeighted + testWeighted) * 100);
            System.out.println("Your total course grade is " + courseScore);
        }

}

Answer 1

方法hwpoints，midTerm和finalScore都返回一个您不保留的int值

您需要做类似的事情

int hwp = hwpoints ();
int mt = midterm ();
int fs = finalScoare ();

然后您可以将这些变量作为{p>传递给courseScore

courseScore (fs, mt, hwp);

注意

在此代码中

int testWeighted = (finalsScore * (testWeight / 100));

您将要进行整数除法。
参见Int division: Why is the result of 1/3 == 0?

Answer 2

首先是要了解类和静态方法的概念。

类具有字段和方法。
- 字段（变量）保存方法可以对其进行操作的数据（状态）
- 每个类的实例在这些字段中都有自己的值
- 方法在字段上起作用
- 方法可以包含调用参数
- 方法也可以返回值
静态实例（类，字段和方法）是单例
- 它们只有一个副本（该类的所有实例都共享一个）
- 静态方法无法访问（非静态）字段/方法

使用此方法，请考虑创建具有GradeCalc类的（大部分）内容的另一个类，并从它们中删除静态变量，并在GradeCalc中创建该类的实例。这样，类中的每个方法都可以访问您定义的字段。

这里是一个基于您已经写过的概念的示例。注意：您的代码还有其他结构/实现问题，我将永远不会如图所示实现它；但是，我不想将其转变为Java课程。因此，我试图向您展示一些可以在您所写内容范围内起作用的东西。

public class GradeCalc {
  public static void main(String[] args) {
      Scanner scanner = new Scanner(System.in);
  Calculator calc = new Calculator (calc);
  calc.hwpoints();
  calc.midTerm();
  calc.courseScore();
  int overAll = calc.OverAll;
  int midtermScore = calc.MidtermScore;;
  int overAll = calc.OverAll;
}
public class Calculator {
  public void OverAll;
  public void MidtermScore;
  public void FinalsScore;

  public void hwpoints()
  {
    ...
    OverAll = overAll
  }
  //Do the same for the methods below
  //public void midTerm();
  //public void courseScore();  
}

如何将变量从一种方法传递到另一种方法？

2 个答案: