Question

In Java, Please do not forget the ToString method in the Student class!

In this exercise, you will first create a Student class. A Student has two attributes: name (String) and gradePointAverage (double). The class has a constructor that sets the name and grade point average of the Student. It has appropriate get and set methods. As well, there is a toString method that prints the student's name and their grade point average (highest is 4.0) You will then write a demo program. In the demo program, you will create an ArrayList of Students. You will populate the arraylist with user inputted data. You should store the students alphabetically by name (A to Z) in the arraylist The algorithm to sort is simple. As you read in each name for the Student (say name1), compare it with each name (say name2 of a Student) stored in the arraylist starting from the index 0. As soon (name1.compareTo(name2) >0) that is the right index to put name1. Be sure that you do not cross the arraylist boundary In addition, you will write a method in your demo class that will take in your arraylist of students and return a new arraylist with the students sorted by their grade point average (highest to lowest). You can apply the same sort algorithm that vou used for the names. See below for a sample output. Enter student name or quit: Bush, Sue Enter grade point aye; 3.4 Enter student name or quit: Neddle, Ned Enter grade point ave; 3.2 Enter student name or quit: Zhang, Bin Enter grade point ave; 3.7 Enter student name or quit: Adda, Ida Enter grade point ave; 3.9 Enter student name or quit: quit Students [ Adda. Ida Grade Point Ave: 3.9, Bush, Sue Grade Point Ave: 3.4, Neddle. Ned Grade Point Ave: 3.2, Zhang, Bin Grade Point Ave: 3.7] Students in order of Grade Point Average [ Adda, Ida Grade Point Ave: 3.9Zhang, Bin Grade Point Ave: 3.7, Bush, Sue Grade Point Ave: 3.4, Neddle. Ned Grade Point Ave: 3.2]

Answer 1

Hi

The following code includes 2 classes

1. Student.java with required member variables and methods
2. StudentDemo.java is the driver program to create the Student objects, add them to sorted list and also sorts them by Grade Point Average

I have included comments inline with the code for your reference. Hope that helps.

Let me know if you need any help.


//File: Student.java

public class Student {
//Member variables
private String name;
private double gradePointAverage;
//Constructors
public Student(String newName, double newGradePointAverage) {
name = newName;
gradePointAverage = newGradePointAverage;
}
//Getters and Setters for the member variables
public void setName(String newName) {
name = newName;
}
public String getName() {
return name;
}
public void setGradePointAverage(double newGradePointAverage) {
gradePointAverage = newGradePointAverage;
}
public double getGradePointAverage() {
return gradePointAverage;
}
//Override the String representation of this class
public String toString() {
return name + " Grade Point Ave:" + gradePointAverage;
}
}




//File: StudentDemo.java

D Student-Java 2 public class Student 4 5 6 //Member variables private String name; private double gradePointAverage 8 //Constructors public Student (String newName, double newGradePointAverage) 9e 10 name- newName gradePointAveragenewGradePointAverage; 12 13 //Getters and Setters for the member variables public void setName(String newName) 15e 16 17 18 name newName; 19 public String getName) 20 21 return name; public void setGradePointAverage (double newGradePointAverage) 23 24 25 26 gradePointAveragenewGradePointAverage; 27 public double getGradePointAverage)i return gradePointAverage 28 29 30 31 32e //Override the String representation of this class public String toString) return name" Grade Point Ave"gradePointAverage; 34 35 36

import java.util.Scanner;
public class StudentDemo {
//Member variable - ArrayList of Students
private static ArrayList<Student> studentList = new ArrayList<>();
//Method to add Student into the list in the alphabetical order of their names
private static void addStudent(Student newStudent) {
boolean addedToList = false;
for(int i = 0; i < studentList.size(); i++) {
Student student = studentList.get(i);
if(student.getName().compareTo(newStudent.getName()) > 0) {
studentList.add(i, newStudent);
addedToList = true;
break;
}
}
//Case: when the list is empty
if(!addedToList) {
studentList.add(newStudent);
}
}
//Method - returns an Arraylist of Students sorted by the Grade Point Average
private static ArrayList<Student> sortByGradePointAverage(ArrayList<Student> studentList) {
ArrayList<Student> sortedStudentList = new ArrayList<>();
for(int i = 0; i < studentList.size(); i++) {
Student student = studentList.get(i);
boolean addedToSortedList = false;
for(int j = 0; j < sortedStudentList.size(); j++) {
Student sortedStudent = sortedStudentList.get(j);
if(student.getGradePointAverage() >= sortedStudent.getGradePointAverage()) {
sortedStudentList.add(j, student);
addedToSortedList = true;
break;
}
}
if(!addedToSortedList) {
sortedStudentList.add(student);
}
}
return sortedStudentList;
}
public static void main(String[] args) {
Scanner inputScanner = new Scanner(System.in);
//Read the input from user
while(true) {
System.out.print("Enter student name or quit: ");
String name = inputScanner.nextLine();
if(name.equalsIgnoreCase("quit")) {
break;
}
System.out.print("Enter grade point ave: ");
String gradePointAverageStr = inputScanner.nextLine();
double gradePointAverage = 0.0d;
//Precaution to ensure Grade Point Average is valid input
try {
gradePointAverage = Double.parseDouble(gradePointAverageStr);
if(gradePointAverage > 4.0d) {
gradePointAverage = 4.0d;
}
} catch(NumberFormatException numFormatEx) {
//In case of invalid GradePointAverage, consider it as zero
}
//Create Student object and add to the list
Student newStudent = new Student(name, gradePointAverage);
addStudent(newStudent);
}
inputScanner.close();
//Display the results
System.out.println("\n\nStudents");
System.out.println(studentList);
System.out.println("Students in order of Grade Point Average:");
System.out.println(sortByGradePointAverage(studentList));
}
}

DStudentDemo.java Ex java.util.Scanner; 1 import 2 3 public class StudentDemo 4 /Member variable ArrayList of Students private static ArrayList<Student> studentListnew ArrayList<>); 6 //Method to add Student into the list in the alphabetical order of their names private static void addStudent(Student newStudent)f 8 10 boolean addedToList = false for(inti-e i < studentList.size() i++) { 13 14 15 16 17 18 19 Student studentstudentList.get(i); if(student.getName().compareTo (newStudent.getName()) θ) { > studentList.add(i, newStudent); addedToList = true ; break; 21 //Case: when the list is empty if(!addedToList) { 23 24 25 26 27 28 29 39Θ studentList.add (newStudent); //Method returns an Arraylist of Students sorted by the Grade Point Average private static ArrayList«Student» sortByGradePointAverage (ArrayList«Student» studentList) { 32 ArrayList<Student> sortedStudentList new ArrayList<>) 34 35 36 37 38 39 for(int i=0; î< studentList . size ( ); i++) { Student student studentList.get(i); boolean addedToSortedList false for(int j- 0;j<sortedStudentList.size); j++) 1 Student sortedStudentsortedStudentList.get(j); 41 42 43 if(student.getGradePointAverage) sortedStudent.getGradePointAverage)) sortedStudentList.add(j, student); addedToSortedList true; break; 45 46 47 48 49 if (!addedToSortedList) sortedStudentList.add (student); 52 53 54 return sortedStudentList; 56 57 58

59 60 public static void main (String args) 61 62 63 64 65 Scanner inputScanner new Scanner (System.in) //Read the input from user while(true) f System.out.print ("Enter student name or quit: "); String nameinputScanner.nextLine); if (name.equalsIgnoreCase("quit")) 68 69 break 71 72 System.out.print("Enter grade point ave: "); 74 75 76 String gradePointAverageStr-inputScanner.nextLine(); double gradePointAverage 0.0d; //Precaution to ensure Grade Point Average is valid input 78 79 try gradePointAverageDouble.parseDouble(gradePointAveragestr); if (gradePointAverage > 4.0d) 81 82 83 84 85 86 87 gradePointAverage-4.0d; catch (NumberFormatException numFormatEx) //In case of invalid GradePointAverage, consider it as zero //Create Student object and add to the list Student newStudentnew Student (name, gradePointAverage) addStudent(newStudent); 89 90 91 92 93 94 95 96 97 98 inputScanner.close); //Display the results System.out.println("\n\nStudents"); System. out.println (studentList); System.out.println( "Students in order of Grade Point Average:") System.out.println (sortByGradePointAverage(studentList)); 100 101 102 103

//Output

bin java StudentDemo Enter student name or quit: Bush, Sue Enter grade point ave: 3.4 Enter student name or quit: Neddle, Ned Enter grade point ave: 3.2 Enter student name or quit: Zhang, Bin Enter grade point ave: 3.7 Enter student name or quit: Adda, Ida Enter grade point ave: 3.9 Enter student name or quit: quit Students Adda, Ida Grade Point Ave:3.9, Bush, Sue Grade Point Ave:3.4, Neddle, Ned Grade Point Ave:3.2, Zhang, Bin Grade Point Ave:3.7] tudents in order of Grade Point Average: Adda, Ida Grade Point Ave:3.9, Zhang, Bin Grade Point Ave:3.7, Bush, Sue Grade Point Ave:3.4, Neddle, Ned Grade Point Ave:3.2 bin