組合兩個不同數據類型的數組

Question

import java.util.Scanner;

public class scores
{
    static Scanner input = new Scanner(System.in);
    public static void main(String[] args)
    {
        System.out.print("\f");
        int classSize, counterScore, counterName;
        String name;
        double score,average, sum;

        System.out.print("Enter size of class: ");
        classSize = input.nextInt();

        int[] scoreArray = new int[classSize];
        String[] nameArray = new String[classSize];

        counterScore=1;
        counterName = 1;
        average = 0;
        sum = 0;

        for (int x = 0; x < classSize; x++)
        {
            input.nextLine();
            System.out.print("Student " + counterName++ + " Name: ");
            nameArray[x] = input.nextLine();
            System.out.print("Student " + counterScore++ + " Score: ");
            scoreArray[x] = input.nextInt();

            sum = sum + scoreArray[x];
            average = sum / classSize;
        }

        System.out.println(average);
    }
}

我必須制作一個應用程序，讓我可以說有多少人參加了測試，然后輸入他們的名字和分數。 我使用了兩個不同的數組，一個是字符串，一個是double。 我的輸出是為了讀取哪些名稱低於平均值並顯示名稱。 我不知道如何組合這兩個數組，以便它識別此分數與此名稱相關，因此顯示該名稱。

Answer 1

我認為你最好的選擇是創建一個包含兩個字段（名稱和分數）的POJO並創建一個數組：

public class Student {
    private String name;
    private int score;

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

    public String getName() {
        return name;
    }

    public int getScore() {
        return score;
    }
}

Answer 2

您可以在一次迭代中簡單地遍歷兩個數組，並填充包含String和double的自定義類型的數組。 （即學生班）

public class Student {
    public String name;
    public double score;
    public Student(String name, double score) {
        this.name = name;
        this.score = score;
    }
}

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

for (int x = 0; x < classSize; x++)
{
    input.nextLine();
    System.out.print("Student " + counterName++ + " Name: ");
    nameArray[x] = input.nextLine();
    System.out.print("Student " + counterScore++ + " Score: ");
    scoreArray[x] = input.nextInt();

    sum = sum + scoreArray[x];
    average = sum / classSize;

    // populate array of student
    students.add(new Student(nameArray[x], scoreArray[x]));
}

請注意，在這種情況下，您不再需要scoreArray和nameArray來獲得更好的內存利用率。

Answer 3

您可以使用（在第一次循環后添加）：

for (int i = 0; i < classSize; i++)
    {
        if(scoreArray[i] < average) {
            System.out.println(nameArray[i])
        }
    }

或者如果你想要一行：

System.out.println("The following students are below average: ")
boolean first = true;
for (int i = 0; i < classSize; i++)
    {
        if(scoreArray[i] < average) {
            if(!first) {
                System.out.println(", ");
                first = false;
            }
            System.out.print(nameArray[i])
        }
    }

另外，你應該移動行average = sum / classSize; 在循環之外，每次重新計算平均值是沒有意義的。

---

要找出最高值，請為名稱保留一個臨時變量，為最高值保留另一個變量，並循環學生：

String highestName = "";
double highestValue = 0;
for (int i = 0; i < classSize; i++) {
    if(scoreArray[i] > highestValue) {
        highestName = nameArray[i];
        highestValue = scoreArray[i];
    }
}
System.out.println(highestName + " has the highest grade.")

如果有關系，可以使用它來打印多個學生：

String[] highestNames = new String[classSize];
int numHighest = 0;
double highestValue = 0;
for (int i = 0; i < classSize; i++) {
    if(scoreArray[i] > highestValue) {
        highestNames[0] = nameArray[i];
        numHighest = 1;
        highestValue = scoreArray[i];
    } else if(scoreArray[i] > highestValue) {
        highestNames[numHighest] = nameArray[i];
        numHighest = numHighest + 1;
    }
}

System.out.println("The following student(s) has/have the highest grade: ")
boolean first2 = true;
for (int i = 0; i < numHighest; i++)
    {
        if(!first2) {
            System.out.println(", ");
            first2 = false;
        }
        System.out.print(highestNames[i])
        }
    }

---

您還可以結合循環內容，打印低於平均成績的學生，以及找到最高成績的學生，以提高您的課程效率：

String[] highestNames = new String[classSize];
int numHighest = 0;
double highestValue = 0;
System.out.println("The following students are below average: ")
boolean first = true;
for (int i = 0; i < classSize; i++)
    {
        if(scoreArray[i] < average) {
            if(!first) {
                System.out.println(", ");
                first = false;
            }
            System.out.print(nameArray[i])
        }
        if(scoreArray[i] > highestValue) {
            highestNames[0] = nameArray[i];
            numHighest = 1;
            highestValue = scoreArray[i];
        } else if(scoreArray[i] > highestValue) {
            highestNames[numHighest] = nameArray[i];
            numHighest = numHighest + 1;
        }
    }