如何在这个 GPA 计算器中构建我的 for 循环？爪哇

Question

如何在这个 GPA 计算器中构建我的 for 循环？刚接触Java，我们班需要4次询问用户的成绩和学分，然后计算他们的平均值。我们被指示使用 switch 语句和循环，但没有太多其他指令。我们刚刚了解了 for、while 和 do 循环。这是我目前所拥有的，不知道下一步该做什么。

This is what output is supposed to look like.

public static void main(String[] args) {
    String grade = "";
    int creditHour = 0;
    int pointsPerCourse = 0;
    double gpa = 0.0;
    
    Scanner scnr = new Scanner(System.in);
    
    System.out.println("\t\t\tpointsPerCourse Calculator");
    System.out.println("This program will calculate pointsPerCourses based on course grades");
    
    for ();
    {
        System.out.print("Enter grade: ");
        grade = scnr.nextLine();
        
        System.out.print("Enter number of credits for grade: ");
        creditHour = Integer.parseInt(scnr.nextLine());
    }
        
    switch (grade) {
        case "A":
            pointsPerCourse = 4 * creditHour;
        case "B":
            pointsPerCourse = 3 * creditHour;
        case "C":
            pointsPerCourse = 2 * creditHour;
        case "D":
            pointsPerCourse = 1 * creditHour;
        default:
            pointsPerCourse = 0 * creditHour;
    }   
            
    gpa = (double) pointsPerCourse / creditHour;
    System.out.printf("The GPA is %.1f ", gpa);

    scnr.close();
}

Answer 1

我认为您正在尝试这样做： 循环 4 次并添加积分和学分进行平均

import java.util.Scanner;

class Prog {
    public static void main(String[] args) {

        String grade = "";
        int creditHour = 0;
        int creditHourSum = 0;
        int pointsPerCourse = 0;
        double gpa = 0.0;

        Scanner scnr = new Scanner(System.in);

        System.out.println("\t\t\tpointsPerCourse Calculator");
        System.out.println("This program will calculate pointsPerCourses based on course grades");

        for (int i = 0; i < 4; i++) {
            System.out.print("Enter grade: ");
            grade = scnr.nextLine();

            System.out.print("Enter number of credits for grade: ");
            creditHour = Integer.parseInt(scnr.nextLine());
            creditHourSum += creditHour;

            switch (grade) {

                case "A":
                    pointsPerCourse += 4 * creditHour;
                    break;
                case "B":
                    pointsPerCourse += 3 * creditHour;
                    break;
                case "C":
                    pointsPerCourse += 2 * creditHour;
                    break;
                case "D":
                    pointsPerCourse += 1 * creditHour;
                    break;
                default:
                    pointsPerCourse += 0 * creditHour;
            }
            System.out.println(pointsPerCourse);
        }

        gpa = (double) pointsPerCourse / creditHourSum;
        System.out.println(pointsPerCourse + ", " + creditHourSum);
        System.out.printf("The GPA is %.1f ", gpa);

        scnr.close();

    }
}

输出

This program will calculate pointsPerCourses based on course grades
Enter grade: A
Enter number of credits for grade: 4
16
Enter grade: E
Enter number of credits for grade: 4
16
Enter grade: B
Enter number of credits for grade: 4
28
Enter grade: C
Enter number of credits for grade: 3
34
34, 15
The GPA is 2.3

Answer 2

这不是 golang，你不能像这样使用 for 循环，并且你想把你的 switch case 放在循环中。有人建议使用 while 循环，但由于您只想循环 4 次，因此适当的 for 循环将为您完成。

for(int i = 0, i < 4, i++){
 System.out.print("Enter grade: ");
    grade = scnr.nextLine();
    
    System.out.print("Enter number of credits for grade: ");
    creditHour = Integer.parseInt(scnr.nextLine());
    
    switch (grade) 
    {
    
      case "A":
        pointsPerCourse = 4 * creditHour;
      case "B":
        pointsPerCourse = 3 * creditHour;
      case "C":
        pointsPerCourse = 2 * creditHour;
      case "D":
        pointsPerCourse = 1 * creditHour;
        
      default:
        pointsPerCourse = 0 * creditHour;
     }
}