Implement a class Class with the following attributes and methods:

1. A public attribute students which is a array of Student instances.
2. A constructor with a parameter n, which is the total number of students in this class. The constructor should create n Student instances and initialized with student id from 0 ~ n-1

Example

Example 1:

Input: 3Output: [0, 1, 2]Explanation: For 3 students, your cls.students[0] should equal to 0, cls.students[1] should equal to 1 and the cls.students[2] should equal to 2.

Example 2:

Input: 5Output: [0, 1, 2, 3, 4]

注意：

1. ：数组声明不能制定大小（因为只是创建了一个引用变量），数组创建时必须制定大小！
3. Class类：先声明一个数组类型的引用变量，在构造方法中才能使引用变量指向创建的数组，因为有了参数n,知道数组长度后,才能创建数组。

代码：

class Student {    public int id;        public Student(int id) {        this.id = id;    }}public class Class {    public Student[] students; // 声明Student类型数组，即创建一个引用        public Class(int n) {        this.students = new Student[n]; // 创建Student类型数组，将引用（students）指向此数组        for (int i = 0; i < n; i++) {            students[i] = new Student(i);        }    }}