使用多个数组列表的基本Java编程

Question

import java.util.Scanner;
import java.util.ArrayList;
public class QuizAverage
{
    public static void main( String[] args ) {
        final int NAMELIMIT = 5 ;
        final int QUIZLIMIT = 5 ;
        ArrayList<String> sNames = new ArrayList<String>();
        ArrayList<String> sFamily = new ArrayList<String>();
        Scanner in = new Scanner(System.in);
        //Load the 5 names of the students in the arraylist
        for(int i = 1; i<=NAMELIMIT; i++)
        {
            String[] input = in.nextLine().split("\\s+");

            sNames.add(input[0]);
            sFamily.add(input[1]);
        }
        System.out.println("Name: ");
        System.out.println();
        for(int i=0; i<NAMELIMIT; i++)
        {
            System.out.println("Name: " +sNames.get(i) + " " +    sFamily.get(i));
        }
        System.out.println();
   }
}

ArrayList<Integer> quizMarks = readArrayList(readQuiz.nextLine());

public static ArrayList<Integer> readArrayList(String input)
{
    ArrayList<Integer> quiz = new ArrayList<Integer>();

    int i = 1;
    while (i <= QUIZLIMIT)
    {
       if (readQuiz.hasNextInt()) {
        quiz.add(readQuiz.nextInt());
        i++;
       } else {
           readQuiz.next(); // toss the next read token
       }
   }
   return quiz;
 }
 //Computer the average of quiz marks
 public static void computerAverage(ArrayList<Integer>quiz)
 {
    double total = 0 ;
    for(Integer value : quiz)
    {
        total = total + value;
    }
    total *= MAX_SCORE/100;
   System.out.println("Quiz Avg: "+ total / QUIZLIMIT ); 
  }
 }

Sally Mae 90 80 45 60 75
Charlotte Tea 60 75 80 90 70
Oliver Cats 55 65 76 90 80
Milo Peet 90 95 85 75 80
Gavin Brown 45 65 75 55 80

给出输出

Name: Sally Mae
Name: Charlotte Tea
Name: Oliver Cats
Name: Milo Peet
Name: Gavin Brown

当所需输出为

Name: Sally Mae Quiz Avg: 10.5
Name: Charlotte Tea Quiz Avg: 11.25
Name: Oliver Cats Quiz Avg: 10.95
Name: Milo Peet Quiz Avg: 12.75
Name: Gavin Brown Quiz Avg: 9.6

Answer 1

就像吉姆说的，你应该把标记和同班学生的名字存起来。这样做的原因是，比如说，往前走，你想找到一个叫Raj的学生的标记。

在您的实现中，您必须通过第一个数组查找名为Raj的人的索引，然后转到marks数组中的相同索引。如果初始化第一个数组没有问题，但创建marks数组时有一些问题，则可能会出现错误的标记。

此外，如果您必须为student添加一个新属性，则必须创建一个新数组，然后再添加一个逻辑来读取该数据。

class Student {
    private String name;
    private Double marks;

    public Student(String name, String marks) {
        this.name = name;
        this.marks = marks;
    }

    //getters setters
}

List<Student> students = new ArrayList<Student>();

读完后，您将把对象追加到此列表中

students.add(new Student(name, marks));

计算平均值如下

Double average = 0;
for(Student student: students) {
    average += student.getMarks();
}
average = average / student.size();

查看https://docs.oracle.com/javase/tutorial/collections/streams/reduction.html以获得平均值的其他方法。