Question

初学者Java程序员。我正在尝试制作一个程序，询问用户他们想要输入多少等级。然后，我想将用户输入的等级存储到数组中。最后，我想找到输入成绩的平均值，并打印出平均值以下每个等级的列表。截至目前，我的代码计算用户输入的成绩的平均值，但我无法弄清楚如何打印平均值以下的成绩。我相信问题在于我的最后一个循环，但我无法弄清楚如何解决它。另外，我是否正确实现了数组？感谢每一位花时间帮助我的人！

public static void grades() {
    int q = 0;
    double grades = 0;
    double total = 0;

    Scanner in = new Scanner(System.in);
    // user input how many grades user would like to enter
    System.out.println("How many grades would you like to enter? ");
    q = in.nextInt();

    // user enters # of grades they requested to enter
    for (int counter = 0; counter < q; counter++) { 
        System.out.println("Enter your grades: ");
        grades = in.nextInt();
        // This creates an array that stores the grades the user entered
        double[] scores = new double[] {grades};
        // adds up all elements (grades)
        for (int k = 0; k < scores.length; k++) {
                 total += scores[k]; //sums up entered grades
        }
    }
    total = total / q; //calcs mean
    //loops prints grades less than mean
    for (grades = 0; grades < total; grades++){
        System.out.println(grades);
    }
}

Answer 1

public static void grades(){
    Scanner in = new Scanner(System.in);
    System.out.println("How many grades would you like to enter? "); //user input how many grades user would like to enter
    int q = in.nextInt();

    double[] grades = new double[q];
    double sum = 0;
    for (int counter = 0; counter < q; counter++){ //user enters # of grades they requested to enter
        System.out.println("Enter your grades: ");
        double grade = in.nextInt();
        grades[counter] = grade;
        sum += grade;
    }
    double mean = sum / q;
    System.out.println("Mean: " + mean);
    for (int i = 0; i < q; i++){ //loops prints grades less than mean
        if (grades[i] < mean) {
            System.out.println(grades[i]);
        }
    }
}

Answer 2

你的最后一个循环毫无意义

你应该计算数组中的所有项目，然后做一个IF来测试它是否低于平均值然后打印它，如果它低于平均值

你已经让循环从0重复到平均值......这没有任何意义，就像说一组学生的平均分数是30％现在打印从student0到student30的所有成绩30这没有任何意义去做。你应该对学生31和学生32感兴趣..不要停在30号学生.student1的成绩可能高于平均水平，而学生40的成绩可能低于平均水平。你将学生编号（数组中的位置索引）与成绩混合在一起。

<强> ADDED 你实际上甚至比这更糟糕。因为等级甚至不是一个数组，它是一个带有一个数字的变量。你有一个数组增加一个变量并打印变量，如打印1,2,3,4,5

你打算做一个循环i = 1到n，并打印数组[i] 你正在做一个循环i = 1到n，你正在打印我

你应该弄清楚阵列是什么，而不是担心计算平均值。让你自己更简单的练习测试你做什么/不理解的东西，而不是书中的东西或老师给你的东西。并使用您的探索来理解您的老师/书给您的练习。

Answer 3

您的代码存在一些问题。首先关闭你的数组，每次迭代都会输入一个新的等级，这将导致一个索引，因为之前的输入正在覆盖它。数组scores应该在for循环之外初始化。

另外，用于打印成绩的for循环不正确。您需要迭代scores数组并打印出每个单独的值。

以下代码适用并演示出错的地方：

public static void grades() {
    int q = 0;
    double grades = 0;
    double total = 0;

    Scanner in = new Scanner(System.in);
    // user input how many grades user would like to enter
    System.out.println("How many grades would you like to enter? ");
    q = in.nextInt();
    double[] scores = new double[q];//initialize here
    // user enters # of grades they requested to enter
    for (int i = 0; i < scores.length; i++) {
        System.out.println("Enter your grades: ");
        grades = in.nextInt();
        // This creates an array that stores the grades the user entered
        scores[i] = grades;//append values to each index
        // adds up all elements (grades)
        total += scores[i]; //sums up entered grades
    }
    total = total / q; //calcs mean
    System.out.println("Mean: " + total);
    //iterate through the scores array with filled values
    for (int i = 0; i < scores.length; i++) {
        System.out.println("Grade #" + i + ": " + scores[i]);
    }
}

Answer 4

可能是什么问题..总数和平均数是错误的。

import java.io.*;

 class overloading2
{
    String name;
    int year;
    String section;
    String subject[];
    double grade[];
    double average;


    public void enrolSubjects()throws Exception
    {
        DataInputStream mat=new DataInputStream(System.in);
        try
        {

            System.out.println("Enter 3 subject:");
            subject=new String[3];

            for(int sub=0;sub<3;sub++)
            {
                subject[2]=(mat.readLine());
            }   
        }
        catch(IOException ioe)
        {   
        }
    }
    public double enterGrades(double grade1,double grade2,double  grade3)
    {
        DataInputStream math=new DataInputStream(System.in);
        try
        {
            System.out.println("Enter 3 grades:");
            grade=new double[3];

            for(int x=0; x<3; x++)
            {
                grade[2]=Double.parseDouble(math.readLine());
            }   
        }

        catch(IOException ioe)
        {

        }
        return enterGrades();
    }
    double enterGrades()
            {
                    double total=0.0;
                    for(int x=0; x<3; x++)
                    {

                            total+=grade[2];
                            average=total/3;
                    }

                    return average;
            }
    public static void main(String []args)throws Exception
    {
        overloading2 ostud1=new overloading2();
        double a=0.0,b=0.0,c=0.0;
        ostud1.enrolSubjects();
        ostud1.enterGrades(a,b,c);
        System.out.println("average grade is "+ostud1.enterGrades());

    }

}

Java - 计算存储在数组+打印等级以下的等级的平均值

4 个答案: