Question

A teacher wants to create a list of students in her class.

Using the existing Student class in this exercise. Create a static ArrayList called classList that adds a student to the classList whenever a new Student is created.

In the constructor, you will have to add that Student to the ArrayList.

Coding below was given to edit and use

public class ClassListTester

{

public static void main(String[] args)

{

//You don't need to change anything here, but feel free to add more Students!

Student alan = new Student("Alan", 11);

Student kevin = new Student("Kevin", 10);

Student annie = new Student("Annie", 12);

System.out.println(Student.printClassList());

}

}

import java.util.ArrayList;

public class Student

{

private String name;

private int grade;

//Implement classList here:

  

public Student(String name, int grade)

{

this.name = name;

this.grade = grade;

  

}

  

public String getName()

{

return this.name;

}

  

/*Don't change the code in this method!

This method will print out all the Student names in the classList Array

*/

public static String printClassList()

{

String names = "";

for(Student name: classList)

{

names+= name.getName() + "\n";

}

return "Student Class List:\n" + names;

}

}

Answer 1

I have created a static ArrayList called classList. I am using this keyword  to represent the current state of object in the constructor of Student Class. Please find attached code ,screenshot and output.

/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

import java.util.ArrayList;

public class ClassListTester
{
public static void main(String[] args)
{
//You don't need to change anything here, but feel free to add more Students!
Student alan = new Student("Alan", 11);
Student kevin = new Student("Kevin", 10);
Student annie = new Student("Annie", 12);
System.out.println(Student.printClassList());
}
}

class Student // This should not be public as java allows only one public class in a java file
{
private String name;
private int grade;
//Implement classList here:
static ArrayList<Student> classList = new ArrayList<Student>(); // This is the arrayList declaration
  
public Student(String name, int grade)
{
this.name = name;
this.grade = grade;
classList.add(this); // Adding current object to the classList
}
  
public String getName()
{
return this.name;
}
  
/*Don't change the code in this method!
This method will print out all the Student names in the classList Array
*/
public static String printClassList()
{
String names = "";
for(Student name: classList)
{
names+= name.getName() + "\n";
}
return "Student Class List:\n" + names;
}
}

1 /* package whatever; // don't place package name! */ import java.util.*; import java.lang.*; import java.io.*; au 7 import java.util.ArrayList; 9 public class ClassListTester 10 - { 11 public static void main(String[] args) 12 - { 13 //You don't need to change anything here, but feel free to add more Students! 14 Student alan = new Student ("Alan", 11); 15 Student kevin = new Student("Kevin", 10); 16 Student annie = new Student("Annie", 12); System.out.println(Student.printClasslist()); 21 class Student // This should not be public as java allows only one public class in a java file 22 - { 23 private String name; 24 private int grade; //Implement classlist here: 26 static ArrayList<Student> classList = new ArrayList<Student>(); // This is the arrayList declaration 28 public Student(String name, int grade) 29 - { 30 this.name = name; 31 this.grade = grade; 32 classList.add(this); // Adding current object to the classList 33 } 34 35 public String getName() 36 - { 37 return this.name; 38 } 39 40- /*Don't change the code in this method!

13 //You don't need to change anything here, but feel free to add more Students! 14 Student alan = new Student ("Alan", 11); 15 Student kevin = new Student("Kevin", 10); 16 Student annie = new Student("Annie", 12); 17 System.out.println(Student.printClasslist()); 18 } 19 } 20 21 class Student // This should not be public as java allows only one public class in a java file 22 - { 23 private String name; 24 private int grade; 25 //Implement classlist here: 26 static ArrayList<Student> classList = new ArrayList<Student>(); // This is the arrayList declaration! 28 public Student(String name, int grade) 29 - { 30 this.name = name; 31. this.grade = grade; 32 classList.add(this); // Adding current object to the classList 33 } 34 35 public String getName() 36 - { 37 return this.name; 38 } 39 40 /*Don't change the code in this method! 41 This method will print out all the Student names in the classList Array 42 */ public static String printClassList() 44 - { 45 String names = ""; for(Student name: classList) 47 - { 48 names+= name.getName() + "\n"; 49 } 50 return "Student Class List:\n" + names; 51 } 52 }

OUTPUT:

37 return this.name; 381 Input Goes Here.. Copy > Run > Run+URL (Generates URL as well) Time(sec): 0.08 Memory(MB): 44.5938 Output: Copy Student Class List: Alan Kevin Annie