Question

创建一个代表测试分数平均值的课程。让课程获得无限数量的分数，并计算测试次数和平均分数。

我似乎无法找到存储所有测试分数的方法，也无法计算给定文件中的测试数量。目前，此代码仅计算其中一个测试，并且仅存储给定的最后一个数字。

此文件由教师提供，无法更改

public class TestScoresDemo {

    public static void main(String[] args) {
        TestScores t1 = new TestScores("Alice");
        TestScores t2 = new TestScores("Bob");

        t1.addTestScore(50);
        t1.addTestScore(60);
        t1.addTestScore(54);
        t1.addTestScore(73);
        t1.addTestScore(88);
        t1.addTestScore(92);

        t2.addTestScore(87);
        t2.addTestScore(97);
        t2.addTestScore(37);
        t2.addTestScore(99);

        System.out.println("-- Alice --");
        System.out.println("Num tests taken: " + t1.getNumTestsTaken());
        System.out.println("Average: " + t1.getAverage());

        System.out.println("-- Bob --");
        System.out.println("Num tests taken: " + t2.getNumTestsTaken());
        System.out.println("Average: " + t2.getAverage());
    }
}

教师给出的文件结尾。以下是我到目前为止的情况。

import java.util.Scanner;

public class TestScores {
    private String Name;
    private double TotalScore;
    private int NumScores;
    private double Earned;

    public TestScores(String name) {
        Name = name;
    }

    public void addTestScore(double earned) {
        Earned = earned;
    }

    public int getNumTestsTaken() {

        NumScores = 0;
        while (Earned < 100.0) { 
            NumScores++;
        }
        return NumScores;
    }

    public double getAverage() {
        try (Scanner scanner = new Scanner(Name)) {
            double sum = 0.0;
            while (Earned <100.0) {
                sum += Earned;
                TotalScore = sum / NumScores;
                break;
            }
            return TotalScore;
        }
    }
}

Answer 1

您没有正确使用变量NumScores或TotalScore。此外，您应该使用变量的Java命名约定，因此将名称中的第一个字母更改为小写字母，然后使用国会大厦字母，AKA驼峰案例。请尝试以下

public TestScores(String name) {
    this.name = name;
    numScores = 0;
    totalScore = 0.0;
}

public void addTestScore(double earned) {
    totalScore += earned; //add to the running total
    numScores++; //add to the count
}

public int getNumTestsTaken() {
    return numScores; //simply return the counter
}

public double getAverage() {
    return totalScore/numScores; //return the total scores added up divided by the count
}

Answer 2

有两种方法可以解决这个问题，两者都在上面的评论中讨论过：

使用list / array / collection存储每个值
添加新元素时加班的数字

正如您的要求所说，TestScores类无法更改，那么它会从可能的解决方案¹中留下第一种方法，这使得第二种方法唯一可行的答案。

但在写下答案之前，我将拯救@Turing85的comment

对整体代码设计的评论：变量和字段名称应始终以小写字母开头（private String Name; - ＆gt; private String name;）。

因此，您的TestScores属性可能会变为：

private String name;
private double totalScore;
private int numScores;
private double earned;

这将使您和我们所有人更容易阅读您的程序。阅读并关注Java naming conventions。

现在让我们看看你的程序现在正在做什么：

t1.addTestScore(50); //earned = 50
t1.addTestScore(60); //earned = 60
t1.addTestScore(54); //earned = 54

你想要什么：

t1.addTestScore(50); //earned = 50
t1.addTestScore(60); //earned = 110
t1.addTestScore(54); //earned = 164

您需要做的就是（在将变量名更改为小写字母后）：

public void addTestScore(double earned) {
    this.earned += earned; //This will be adding every number you send to it to the total
    this.numScores++; //This keeps track of the number of tests taken
}

现在getNumTestsTaken方法可能会变成：

public int getNumTestsTaken() {
    return numScores;
}

你的getAverage方法会变成这样：

public double getAverage() {
    return earned / numScores; //We already know the total amount earned as it's stored in "earned" variable and the number of scores stored in "numScores" so, this becomes a simple operation
}

对于其余的代码，我认为没问题。

¹ _{我要从这个答案中删除数组/集合，但是如果有人想要添加它以及答案，那么将这个答案作为社区维基。但是我已经在这里解释了为什么这不适合（根据OP的要求）。}

创建一个代表测试分数平均值的课程

2 个答案: