Question

我想按照升序排序学生班的3个对象学生班级中浮点数组的计算平均值。我创建了一个接受两个参数并返回学生平均值的界面，但我不确定如何按计算的平均值对学生班级的3个对象进行排序。

public class Student implements ICalculateAvg
{
    private String name;
    private String gender;
    private String idNumber;
    private Subject subject;

    //Getters and setters

    @Override
    public float calculateAverage(float firstGrade, float secondGrade) {
        return (firstGrade+secondGrade)/subject.getGrade().length;
    }
}

public class Subject 
{
    private String subjectCode[];
    private String  name[];
    private float grade[];

    //  Getters and setters
}

打印学生班级的内容会产生以下输出。

Student [name=Mary, gender=Female, idNumber=105, subject=Subject [subjectCode=[SPN3010, FRN1720], name=[Spanish, French], grade=[78.0, 98.0]]]
Student [name=John, gender=Male, idNumber=102, subject=Subject [subjectCode=[SPN3010, FRN1720], name=[Spanish, French], grade=[90.0, 91.0]]]
Student [name=James, gender=Male, idNumber=101, subject=Subject [subjectCode=[SPN3010, FRN1720], name=[Spanish, French], grade=[12.0, 34.0]]]

这是我主要方法中的一些内容。我试图使用比较器和类似的界面来完成所需的结果，但我无法让它工作。

float [] studenGrades1 = {12f, 34f};
float [] studenGrades2 = {90f, 91f};
float [] studenGrades3 = {78f, 98f};

Student student1 = new Student("James Brown", "Male", "101", new Subject(subjectCode, subjectName, studenGrades1));
Student student2 = new Student("John Doe", "Male", "102", new Subject(subjectCode, subjectName, studenGrades2));
Student student3 = new Student("Mary Jame", "Female", "105", new Subject(subjectCode, subjectName, studenGrades3));

float studentFinalGrade1 = student1.calculateAverage(student1.getSubject().getValueAtArrayIndex(0), student1.getSubject().getValueAtArrayIndex(1));
float studentFinalGrade2 = student2.calculateAverage(student2.getSubject().getValueAtArrayIndex(0), student2.getSubject().getValueAtArrayIndex(1));
float studentFinalGrade3 = student3.calculateAverage(student3.getSubject().getValueAtArrayIndex(0), student3.getSubject().getValueAtArrayIndex(1));

Answer 1

我没有给出完整的代码，只有逻辑：

            Collections.sort(studentList, new Comparator<Student>() {
            @Override
            public int compare(Student s1, Student s2) {
                float grade1[] = s1.getSubject().getGrade();
                float grade2[] = s2.getSubject().getGrade();
                Float avg1=null;//calculate average from grade1
            Float avg2=null;//calculate average from grade2

            return avg1.compareTo(avg2);
            }
        });

如何根据数组中值的平均值按升序对类的实例进行排序？

1 个答案: