我无法增加 For 中的 studentid 值

Question

我正在 Java 中进行一些编码，但它不起作用：

导入java.util.Scanner；

导入java.util.Arrays；

public class 主要 {

    public static void main(String[] args) 
    {
        Scanner input = new Scanner(System.in);

        String [] studentId = new String [3];

        Student name;

        for (int i = 0; i < 3; i++) 
        {
        System.out.print("Enter Name => ");
        name = new Student(input.next());
        studentId[i] = name.toString();
        }
        for (int i = 0; i < 3; i++) 
        {
        System.out.println(studentId[i]);
        }    
}
}

public class Student
{
    private static int studentId;
    private String name;

    public Student(String name) 
    {
    this.name=name;    
    setStudentId(studentId++);
    }

    public int getStudentId() 
    {
    return studentId;
    }

    public void setStudentId(int studentId) 
    {
    this.studentId = studentId;
    }

    @Override
    public String toString()
    {
        return (this.studentId +" "+ "student is "+ " " + "(" + this.studentId + ")"+ this.name);
    }
}

我需要在创建新条目时自动增加 ID。我什么都试过了，还是不能增加。

Answer 1

您正在为每个人的 ID 使用静态变量。您需要一个单独的非静态字段来存储每个单独的 ID。

public class Student
{
    private static int nextAvailableStudentId = 1;
    private String name;
    private int studentId;

    public Student(String name) 
    {
    this.name=name;    
    setStudentId(nextAvailableStudentId++);
    }

    public int getStudentId() 
    {
    return studentId;
    }

    public void setStudentId(int studentId) 
    {
    this.studentId = studentId;
    }

    @Override
    public String toString()
    {
        return (this.studentId +" "+ "student is "+ " " + "(" + this.studentId + ")"+ this.name);
    }
}

Answer 2

在构造函数中应该是：

{
    public Student(String name) 
    {
        this.name=name;    
        setStudentId(studentId + 1);
    }
}

我无法增加 For 中的 studentid 值

I can not increase the studentid value in For

java

arrays

for-loop

auto-increment