正确格式化我的输出

Question

I'm trying to make my code will display the highest score, lowest score, and average score of a teacher's class.

I want it to display like this:

Highest Score: 94.7, Jake

Lowest Score: 80.2, Emily

Average Score: 85.6

The highest grade and the average grade works, but the lowest grade doesn't. This is what I have so far:

import java.util.*;

public class Grades {
    public static void main(String[] args) {
        ArrayList<Integer> bestStudentPosition = new ArrayList<Integer>();
        ArrayList<Integer> worstStudentPosition = new ArrayList<Integer>();
        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]; 
        double maxGrade = 0;
        double minGrade = scores[0];
        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];

              if (scores[i] > maxGrade) {
                  bestStudentPosition.clear(); 
                  maxGrade = scores[i];
                  bestStudentPosition.add(new Integer(i));
              } 
              else if (scores[i] == maxGrade) {
                   bestStudentPosition.add(new Integer(i)); 
              }
              if (scores[i] < minGrade) {
                  worstStudentPosition.clear(); 
                  minGrade = scores[i];
                  worstStudentPosition.add(new Integer(i));
              } 
              else if (scores[i] == minGrade) {  
                   worstStudentPosition.add(new Integer(i)); 
              }

         }

         avg = sum/totalStudents;  
         System.out.print("Highest score: ");
         for (Integer position : bestStudentPosition) { 
             System.out.println(maxGrade + ", " + names[position]);
         }
         System.out.print("Lowest score: ");
         for (Integer position : worstStudentPosition) { 
              System.out.println(minGrade + ", " + names[position]);
         }

         System.out.printf("Average: %3.2f", avg);

    }
}

Any help would be appreciated.

Answer 1

scores[i] < minGrade

where minGrade is 0 initially and you are never assigning it any value other than 0. Also, this will only work if grade will be less than 0.

So, probably what you need to do is,

import java.util.ArrayList;
import java.util.Scanner;

public class Grades {
    public static void main (String[] args) {
        ArrayList<Integer> bestStudentPosition  = new ArrayList<Integer>();
        ArrayList<Integer> worstStudentPosition = new ArrayList<Integer>();
        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];
        double   maxGrade      = 0;
        double   minGrade      = 0;
        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];
            if (i == 0) {
                minGrade = scores[0];
            }
            if (scores[i] > maxGrade) {
                bestStudentPosition.clear();
                maxGrade = scores[i];
                bestStudentPosition.add(new Integer(i));
            } else if (scores[i] == maxGrade) {
                bestStudentPosition.add(new Integer(i));
            }
            if (i > 0 && scores[i] < minGrade) {
                worstStudentPosition.clear();
                minGrade = scores[i];
                worstStudentPosition.add(new Integer(i));
            } else if (scores[i] == minGrade) {
                worstStudentPosition.add(new Integer(i));
            }

        }

        avg = sum / totalStudents;
        System.out.print("Highest score: ");
        for (Integer position : bestStudentPosition) {
            System.out.println(maxGrade + ", " + names[position]);
        }
        System.out.print("Lowest score: ");
        for (Integer position : worstStudentPosition) {
            System.out.println(minGrade + ", " + names[position]);
        }

        System.out.printf("Average: %3.2f", avg);

    }
}

assign minGrade with initial value of scores[0] before these conditions. eg

minGrade = scores[0];

This is the output:

How many students are in your class? 3

Name: Harry

Score: 90.2

Name: Laurent

Score: 99.99

Name: Darren

Score: 98.9

Highest score: 99.99, Laurent

Lowest score: 90.2, Harry

Average: 96.36