java - 在java中实现类和对象，调用方法

Question

我在调用方法时遇到问题。该程序的基础是从 data.txt 读取数据，获取给定的名称标记，然后获取后面的所有成绩，然后对成绩执行一些操作以提供该人的成绩的详细信息。我在一个名为 Grades.java 的单独文件中执行所有方法，该文件具有 Grades 类。我只是遇到麻烦，因为我的代码中必须有 testGrades 方法(我认为没有必要)。我已经完成了我需要做的一切，以便在不同的程序中获得完美的结果，而无需使用两个不同的 .java 文件。但必须这样做。我想我基本上已经确定了所有事情，我只是对如何实现和调用 testGrades 方法感到困惑。我将其注释掉并询问它在程序中的位置。对于类和对象以及一般的 java 来说都是相当新的。抱歉问了这个蹩脚的问题。

public class Lab2 {

public static void main(String[] args) {

    Scanner in = null; //initialize scanner
    ArrayList<Integer> gradeList = new ArrayList<Integer>(); //initialize gradeList
     //grab data from data.txt 
    try {
        in = new Scanner(new File("data.txt"));
    } catch (FileNotFoundException exception) {
        System.err.println("failed to open data.txt");
        System.exit(1);
    }
    //while loop to grab tokens from data
    while (in.hasNext()) {
        String studentName = in.next();   //name is the first token
        while (in.hasNextInt()) {   //while loop to grab all integer tokens after name
            int grade = in.nextInt();   //grade is next integer token
            gradeList.add(grade);       //adding every grade to gradeList
        }

      //grab all grades in gradeList and put them in an array to work with
        int[] sgrades = new int[gradeList.size()];
        for (int index = 0; index < gradeList.size(); index++) {
            sgrades[index] = gradeList.get(index);  //grade in gradeList put into grades array 
        }

     //testGrades(sgrades);     How would I implement this method call? 

    }
}

public static void testGrades(Grades grades) {
    System.out.println(grades.toString()); 
    System.out.printf("\tName:    %s\n", grades.getName());
    System.out.printf("\tLength:  %d\n", grades.length());
    System.out.printf("\tAverage: %.2f\n", grades.average());
    System.out.printf("\tMedian:  %.1f\n", grades.median());
    System.out.printf("\tMaximum: %d\n", grades.maximum());
    System.out.printf("\tMininum: %d\n", grades.minimum());
}

   }

这是 Grades.java 文件开头的一小段

     public class Grades {

private String studentName; // name of student Grades represents
private int[] grades; // array of student grades

public Grades(String name, int[] sgrades) {
    studentName = name; // initialize courseName
    grades = sgrades; // store grades
} 

      public String getName() {
    return studentName;
} // end method getName

public int length() {
    return grades.length; 
}

Answer 1

您的测试成绩采用 Grades 对象，因此您需要使用您的数据构造一个 Grades 对象并将其传递给您的测试成绩方法即

Grades myGrade = new Grades(studentName,sgrades);
testGrades(myGrade);