Java-计算存储在数组中的成绩的平均值+低于平均值的打印成绩

Question

这里是初学者Java程序员。 我正在尝试编写一个程序，询问用户他们想要输入多少个等级。 然后，我要存储用户输入到数组中的成绩。 最后，我想查找输入的成绩的平均值，并打印出低于该平均值的每个成绩的列表。 到目前为止，我的代码计算了用户输入的成绩的平均值，但我不知道如何打印低于平均值的成绩。 我相信问题出在我的最后一个for循环中，但是我不知道如何解决它。 另外，我是否正确实现了数组？ 感谢所有花时间帮助我的人！

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

您的最后一个循环没有意义

您应该对数组中的所有项目进行计数，然后执行IF来测试它是否低于平均值，如果低于平均值则打印它

您已经使循环从0迭代到均值..这根本没有意义，就像说一组学生的平均分数现在是30％一样，现在打印出从student0到student30的所有成绩。这样做是没有意义的。 您应该对学生31和学生32感兴趣。不要停止在学生编号30上。学生1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。 您正在将学生编号（数组中位置的索引）与年级混合在一起。

添加实际上，您所做的甚至比这还糟。.因为成绩甚至都不是数组，所以它是一个只有一个数字的变量。 您有一个数组，该数组增加变量并打印变量，如打印1,2,3,4,5

您打算将i = 1循环到n，并打印array [i]您正在i = 1循环到n，并且您正在打印i

您应该弄清楚数组的意义，而不必担心计算均值。 做一个简单的练习来测试您的理解/理解，而不是书本或老师给您的东西。 并使用您的探索力来理解您的老师/书给您的练习。

Answer 3

您的代码有一些问题。 首先，在每次迭代时都要初始化数组，以输入新的等级，这将导致一个索引，因为先前的输入将其覆盖。 数组scores应在for循环外初始化。

另外，您用于打印成绩的for循环也不正确。 您需要遍历scores数组并打印出每个单独的值。

以下代码可以正常工作，并演示您在哪里出错：

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

总和和平均值是错误的。

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());

    }

}