Question

我制作了一个能够接受教师输入的代码，这样他们就可以计算出他们班级的平均成绩，还有一些其他的东西。

不幸的是，我的代码没有正常工作。我试图让它显示平均等级，但它不断产生错误信息。

我需要代码首先获取类大小。然后记下学生的姓名和成绩。

然后应该计算班级的平均成绩。这就是我到目前为止所做的：

package program;

import java.util.Scanner;
public class FinalGrades{   
        public static void main(String[]args) {
            Scanner input = new Scanner(System.in);
            System.out.print("How many students are in your class? ");
            int totalStudents = Integer.parseInt(input.nextLine());     
            String[] names = new String[totalStudents];
            double[] scores = new double[totalStudents];
            for(int i = 0; i < totalStudents; i++){
                System.out.print("Name: ");
                names[i] = input.next();
                System.out.print("Score: ");
                scores[i] = input.nextDouble();
            }
            double avg = 0;
            double sum = 0;
            for (int j = 0; j<= totalStudents; j++){
                sum += scores[j];
                avg = sum/totalStudents;
                System.out.println("The average score was: " + avg);    
            }

        }

}

我还希望代码显示最高等级，旁边的学生姓名如下：

94.5，雅各布（但现在没有必要）。

Answer 1

您的上次for错误，您不会在那里计算avg，但在for完成后（在您获得sum所有分数后）。其次，在获得成绩后立即计算sum。为了了解最高等级的学生，一旦给出输入，检查最高等级并记住它是否是最大等级。由于可以有多个这样的学生具有相同的最佳成绩，所以保留他们在阵列中的位置。

 ArrayList<Integer> bestStudentPosition = new ArrayList<Integer>();
 ArrayList<Integer> worstStudentPosition = new ArrayList<Integer>();
 double maxGrade = 0;
 double minGrade = 101;
 double avg = 0;
 double sum = 0;
 for(int i = 0; i < totalStudents; i++){
      System.out.print("Name: ");
      names[i] = input.next();
      System.out.print("Score: ");
      scores[i] = input.nextDouble();
      sum += scores[i];
      System.out.println("Running avg: " + (sum / (i + 1)); // for extra points
      if (scores[i] > maxGrade) {
          bestStudentPosition.clear(); // delete all previous students from list
          maxGrade = scores[i];
          bestStudentPosition.add(new Integer(i));
      } 
      else if (scores[i] == maxGrade) {  // if its same as some student(s) before, add this one to list too
           bestStudentPosition.add(new Integer(i)); 
      } else if (scores[i] < minGrade) {
           worstStudentPosition.clear();
           minGrade = scores[i];
           worstStudentPosition.add(new Integer(i));
      } else if (scores[i] == minGrade) {
           minGrade= scores[i];
           worstStudentPosition.add(new Integer(i));
      }

 }

 avg = sum/totalStudents;   // final avg
 System.out.println("The average score was: " + avg);  
 System.out.println("Best student(s):");
 for (Integer position : bestStudentPosition) { // print all best students
      System.out.println(maxGrade + ", " + names[position]);
 }
 System.out.println("Worst student(s):");
 for (Integer position : worstStudentPosition) { // print all worst students
      System.out.println(minGrade + ", " + names[position]);
 }

Answer 2

首先，您需要了解平均概念。它是总数的总和。

你正在做的是多次潜水。

double avg = 0;
double sum = 0;
for (int j = 0; j < totalStudents; j++){
   sum += scores[j];
}
avg = sum/totalStudents;
System.out.println("The average score was: " + avg);

如果你想要一个平均值，你需要做：

double avg = 0;
double sum = 0;
for (int j = 0; j < totalStudents; j++){
   sum += scores[j];
   avg += scores[j] / totalStudents;
   System.out.println("The average score was: " + avg);
}

如何显示阵列的平均值？

2 个答案: