Question

Language Java

Step 1:
Design a class called Student.

The Student class should contain the following data:
firstName
lastName
studentID
totalCredits
gpa

Your class should implement the “sets” and “gets” for the class. Include methods: equals, compareTo, toString. Change the toString method (from class) to put each member variable on a new line.

Step 2:
Write a driver program to test that Student works correctly. Test is with 3 students as given in class.

Step 3:
Write a “registration” program that will store up to students (for now) in an array roster of Student objects.
After the user has entered the information for the 5 students, use the InsertionSort code written in class, and posted on Blackboard, to sort the array roster.

Step 4:
Write a method called storeRosterthat will save the data in the array roster to a text file Roster1.txt.

Step 5:
Write a method called loadRoster that will read the data in Roster1.txt into an array roster. (Note: this data will already be sorted!)

Step 6:
Add a “menu” to your main that will let the user:
loadRoster
add and delete students, keeping the names sorted
storeRoster

Note: We would normally store the names into the same text file at the end, but to make sure all the changes worked, please make a second text file, Roster2.txt to save the data.

Step 7:
Extend the Student class to include an ArrayList of course numbers, example CUS1116, Math 1021, etc.

What I have so far:

public class Student implements Comparable {

    private String firstName;
    private String lastName;
    private String studentId;
    private int totalCredits;
    private double gpa;

   public Student() {
        this.firstName = "";
        this.lastName = "";
        this.studentId = "";
        this.totalCredits = 0;
        this.gpa = 0;
    }

    public Student(String firstName, String lastName, String studentId, int totalCredits, double gpa) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.studentId = studentId;
        this.totalCredits = totalCredits;
        this.gpa = gpa;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

   public String getStudentId() {
        return studentId;
    }

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

    public int getTotalCredits() {
        return totalCredits;
    }

    public void setTotalCredits(int totalCredits) {
        this.totalCredits = totalCredits;
    }

    public double getGpa() {
        return gpa;
    }

    public void setGpa(double gpa) {
        this.gpa = gpa;
    }

    @Override
    public boolean equals(Object o) {
       if (o == null || !(o instanceof Student)) return false;
        Student aStudent = (Student) o;
        return aStudent.getFirstName().equals(getFirstName()) &&
                aStudent.getLastName().equals(getLastName()) &&
                aStudent.getStudentId().equals(getStudentId());
    }


    @Override
    public String toString() {
        return
                "First name: " + firstName +
                        "\nLast Name: " + lastName +
                        "\nStudent Id: " + studentId +
                        "\nTotal credits: " + totalCredits +
                        "\ngpa:" + gpa;

    }

    @Override
    public int compareTo(Student student) {
        if (getFirstName().compareTo(student.getFirstName()) == 0) {
            if (getLastName().compareTo(student.getLastName()) == 0) {
                return getStudentId().compareTo(student.getStudentId());

            } else {
                return getLastName().compareTo(student.getLastName());
            }
        } else {
            return getFirstName().compareTo(student.getFirstName());
        }
    }
}

===========================================================================

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileWriter;

import java.io.IOException;

import java.util.Arrays;

import java.util.Scanner;



public class Registration {



    public static void main(String[] args) {



        // Below code is for Step 2

        Student students[] = new Student[3];

        students[0] = new Student("John", "Doe", "123-45", 40, 4.6);

        students[1] = new Student("John", "Smith", "124-45", 50, 4.7);

        students[2] = new Student("Alan", "Donald", "127-65", 30, 2.7);



        // printing the students

        for (Student student : students) {

            System.out.println(student);

        }



        Arrays.sort(students);

        //insertionSort(students);

        System.out.println("====================");

        System.out.println("Sorting the students");

        System.out.println("====================");



        // printing the students again

        for (Student student : students) {

            System.out.println(student);

        }



        // Step 3



        Student fiveStudents[] = {new Student(), new Student(), new Student(), new Student(), new Student()};

        Scanner scanner = new Scanner(System.in);

        for (int i = 0; i < fiveStudents.length; i++) {

            System.out.println("Student " + (i + 1));

            System.out.print("Enter First Name: ");

            fiveStudents[i].setFirstName(scanner.nextLine());

            System.out.print("Enter Last Name: ");

            fiveStudents[i].setLastName(scanner.nextLine());

            System.out.print("Enter Student ID: ");

            fiveStudents[i].setStudentId(scanner.nextLine());

            System.out.print("Enter total credits (whole number) : ");

            fiveStudents[i].setTotalCredits(scanner.nextInt());

            System.out.print("Enter GPA score: ");

            fiveStudents[i].setGpa(scanner.nextDouble());

            scanner.nextLine();

        }



        insertionSort(fiveStudents);



        // printing the students entered by the user

        for (Student student : fiveStudents) {

            System.out.println(student);

        }



        storeRoster(fiveStudents);

        loadRoster();



    }



    // Step 5

    public static Student[] loadRoster() {



        Student students[] = new Student[5];

        int index = 0;

        String fileName = "Roster1.txt";

        try {

            Scanner fileReader = new Scanner(new File(fileName));

            while (fileReader.hasNextLine()) {

                String tokens[] = fileReader.nextLine().split("\\s+");

                if (tokens.length == 5) {



                    int credits = Integer.parseInt(tokens[3]);

                    double gpa = Double.parseDouble(tokens[4]);



                    students[index++] = new Student(tokens[0], tokens[1], tokens[2], credits, gpa);

                }

            }

        } catch (FileNotFoundException e) {

            System.out.println("Error: Unable to read/open file: " + fileName);

        }



        // printing the students after reading from the file

        System.out.println("=================================================");

        System.out.println("printing the students after reading from the file");

        System.out.println("=================================================");

        for (Student student : students) {

            System.out.println(student);

        }

        return students;

    }



    // Part Step 4

    public static void storeRoster(Student[] students) {

        String fileName = "Roster1.txt";

        try {

            FileWriter writer = new FileWriter(new File(fileName));

            for (Student student : students) {

                writer.write(student.getFirstName() + " ");

                writer.write(student.getLastName() + " ");

                writer.write(student.getStudentId() + " ");

                writer.write(student.getTotalCredits() + " ");

                writer.write(student.getGpa() + "\r\n");

                writer.flush();

            }

            writer.close();

            System.out.println(fileName + " updated successfully");

        } catch (IOException e) {

            System.out.println("Error: Unable to write/open file: " + fileName);

        }

    }



    public static void insertionSort(Student[] students) {



        int n = students.length;

        for (int i = 1; i < n; i++) {

            Student key = students[i];

            int j = i - 1;

            while (j >= 0 && students[j].compareTo(key) > 0) {

                students[j + 1] = students[j];

                j = j - 1;

            }

            students[j + 1] = key;

        }

    }

}
==========================================================================

Answer 1

Student.java

import java.util.ArrayList;

public class Student {
private String firstName, lastName, studentId;
private int totalCredits;
private ArrayList<String> courseNumbers;
private double gpa;
  
public Student()
{
this.firstName = this.lastName = this.studentId = "";
this.courseNumbers = new ArrayList<>();
this.totalCredits = 0;
this.gpa = 0.0;
}

public Student(String firstName, String lastName, String studentId, int totalCredits,
ArrayList<String> courseNumbers, double gpa) {
this.firstName = firstName;
this.lastName = lastName;
this.studentId = studentId;
this.totalCredits = totalCredits;
this.courseNumbers = courseNumbers;
this.gpa = gpa;
}

public String getFirstName() {
return firstName;
}

public String getLastName() {
return lastName;
}

public String getStudentId() {
return studentId;
}

public int getTotalCredits() {
return totalCredits;
}

public ArrayList<String> getCourseNumbers() {
return courseNumbers;
}

public double getGpa() {
return gpa;
}
  
@Override
public String toString()
{
String res = "Student Id: " + this.studentId + "\n"
+ "Name: " + this.firstName + " " + this.lastName + "\n"
+ "Courses: ";
for(String c : this.courseNumbers)
{
res += c + "\n";
}
res += "Total Credits: " + this.totalCredits + "\n"
+ "GPA: " + String.format("%.2f", this.gpa);
return res;
}
}

Registration.java

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;

public class Registration {
private ArrayList<Student> students;
  
public Registration()
{
this.students = new ArrayList<>();
}
  
public void loadRoster(String filename)
{
Scanner fileReader;
int count = 0;
try
{
fileReader = new Scanner(new File(filename));
while(fileReader.hasNextLine())
{
String line = fileReader.nextLine().trim();
String[] data = line.split(",");
String firstName = data[0];
String lastName = data[1];
String studentId = data[2];
int totalCredits = Integer.parseInt(data[3]);
String[] courseData = data[4].split(";");
ArrayList<String> courses = new ArrayList<>();
for(String c : courseData)
{
courses.add(c);
}
double gpa = Double.parseDouble(data[5]);
  
this.students.add(new Student(firstName, lastName, studentId, totalCredits, courses, gpa));
count++;
}
fileReader.close();
System.out.println("\n" + count + " student data were loaded successfully!\n");
}catch(FileNotFoundException fnfe){
System.out.println(filename + " couldn't be found!");
System.exit(0);
}
}
  
public void addStudent()
{
Scanner sc = new Scanner(System.in);
System.out.print("\nEnter first name: ");
String fName = sc.nextLine().trim();
System.out.print("Enter last name: ");
String lName = sc.nextLine().trim();
System.out.print("Enter student Id: ");
String studId = sc.nextLine().trim();
System.out.print("Number of courses: ");
int nCourses = Integer.parseInt(sc.nextLine().trim());
ArrayList<String> courses = new ArrayList<>();
for(int i = 0; i < nCourses; i++)
{
System.out.print("Course #" + (i + 1) + ": ");
courses.add(sc.nextLine().trim());
}
System.out.print("Enter total credits: ");
int totalCredits = Integer.parseInt(sc.nextLine().trim());
System.out.print("Enter GPA: ");
double gpa = Double.parseDouble(sc.nextLine().trim());
  
this.students.add(new Student(fName, lName, studId, totalCredits, courses, gpa));
System.out.println("\n" + fName + " " + lName + " was successfully added to the roster.\n");
}
  
public void deleteStudent()
{
Scanner sc = new Scanner(System.in);
System.out.print("\nEnter the student Id to delete: ");
String studentId = sc.nextLine().trim();
  
// search for the student id
boolean found = false;
int index = -1;
for(int i = 0; i < this.students.size(); i++)
{
if(this.students.get(i).getStudentId().equalsIgnoreCase(studentId))
{
found = true;
index = i;
break;
}
}
  
if(!found)
System.out.println("\nNo student record with Id " + studentId + " were found!\n");
else
{
String name = this.students.get(index).getFirstName() + " " + this.students.get(index).getLastName();
this.students.remove(index);
System.out.println(name + " was successfully deleted from the roster!\n");
}
}
  
public void sortRoster()
{
int len = this.students.size();
for(int i = 1; i < len; ++i)
{
Student key = this.students.get(i);
int j = i - 1;
while(j >= 0 && this.students.get(j).getGpa() > key.getGpa())
{
this.students.set(j + 1, this.students.get(j));
j = j - 1;
}
this.students.set(j + 1, key);
}
System.out.println("\nRoster was successfully sorted by GPA!");
viewRoster();
}
  
public void viewRoster()
{
if(this.students.isEmpty())
System.out.println("\nThe roaster is empty!\n");
else
{
System.out.println("\nROSTER:\n-------");
int count = 0;
System.out.printf("%-15s %-20s %-50s %-20s %-10s\n", "Student Id", "Name", "Courses", "Total Credits", "GPA");
for(Student st : this.students)
{
String co = "";
++count;
for(int i = 0; i < st.getCourseNumbers().size(); i++)
{
if(i == st.getCourseNumbers().size() - 1)
co += st.getCourseNumbers().get(i);
else
co += st.getCourseNumbers().get(i) + ", ";
}
System.out.printf("%-15s %-20s %-50s %-20d %-10.2f\n", st.getStudentId()
, st.getFirstName() + " " + st.getLastName(), co, st.getTotalCredits(), st.getGpa());
}
System.out.println("Roster strength: " + count + "\n");
}
}
  
public void storeRoster(String filename)
{
FileWriter fw;
PrintWriter pw;
try {
fw = new FileWriter(new File(filename));
pw = new PrintWriter(fw);
  
for(Student st : this.students)
{
pw.write(st.getFirstName() + "," + st.getLastName() + "," + st.getStudentId() + ","
+ st.getTotalCredits() + ",");
for(int i = 0; i < st.getCourseNumbers().size(); i++)
{
if(i == st.getCourseNumbers().size() - 1)
pw.write(st.getCourseNumbers().get(i) + ",");
else
pw.write(st.getCourseNumbers().get(i) + ";");
}
pw.write(String.format("%.2f", st.getGpa()) + System.lineSeparator());
}
  
pw.flush();
fw.close();
pw.close();
System.out.println("\nRoster has been successfully written to " + filename + ".\n");
} catch (IOException ex) {
System.out.println("\nError in writing roster to " + filename + "!\n");
System.exit(0);
}
}
}

RegistrationMainApp.java (Main class)

import java.util.Scanner;

/*
IN THE INPUT FILE (Roster1.txt), the data fields must be separated by comma(,)
AND for the Course Numbers, they should be separated by semi-colon(;)
*/
public class RegistrationMainApp {
  
private static final String IN_FILE = "Roster1.txt";
private static final String OUT_FILE = "Roster2.txt";
  
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
Registration reg = new Registration();
int choice;
  
do
{
displayMenu();
choice = Integer.parseInt(sc.nextLine().trim());
switch(choice)
{
case 1:
{
reg.loadRoster(IN_FILE);
break;
}
  
case 2:
{
reg.addStudent();
break;
}
  
case 3:
{
reg.deleteStudent();
break;
}
  
case 4:
{
reg.sortRoster();
break;
}
  
case 5:
{
reg.viewRoster();
break;
}
  
case 6:
{
reg.storeRoster(OUT_FILE);
break;
}
  
case 0:
{
System.out.println("\nThanks for visiting us.\nHave a nice day, Goodbye!\n");
System.exit(0);
}
  
default:
System.out.println("\nInvalid selection.\n");
}
}while(choice != 0);
}
  
private static void displayMenu()
{
System.out.print("STUDENT REGISTRATION SYSTEM - Choose from below:\n"
+ "1. Load Roster\n"
+ "2. Add Student\n"
+ "3. Delete Student\n"
+ "4. Sort Roster\n"
+ "5. View Roster\n"
+ "6. Store Roster to File\n"
+ "0. Exit\n"
+ "Your selection >> ");
}
}

***************************************************************** SCREENSHOT **********************************************************

INPUT FILE (Roster1.txt)

OUTPUT FILE (Roster2.txt)

CONSOLE OUTPUT