Question

In Java

a. Create a class called StudentRecord that has the following private variables: year, GPA Implement 2 constructors: default constructor (doesn't take any parameters, has b. an empty body) and a constructor, that initializes all variables. according to the following template: Implement Comparable interface, so that StudentRecord class has ĢompareTo c. Implement a toString() method that returns text representation of an object First name: Benoit, last name: Mandelbrot, year: 3, GPA: 3.68 d. method, that performs comparison as the following: 1. Compare based on GPA 2. If GPA is equal, compare based on year. 3. If years and GPA are equal, compare based on last names; 4. If years, GPA and last names are equal, compare based on first names. e. Create a client class, which: 1. Creates an array list studentRecords 2. Adds the following student records to the list: 1) First name: Jes, last name: Reynaldsson, year: 1, GPA: 3.4; 2) First name: Valeria, last name: Reynaldsson, year: 1, GPA: 3.7; 3) First name: Valeria, last name: Reynaldsson, year: 2, GPA: 3.5; 4) First name: Valeria, last name: Reynaldsson, year: 1, GPA: 3.68; 3. Sorts the list and prints it out 2. Write a method that sorts an array of integers using selection sort.

Answer 1

1.

StudentRecord.java

public class StudentRecord implements Comparable<StudentRecord>{
private String firstName, lastName;
private int year;
private double gpa;
  
public StudentRecord()
{
this.firstName = "";
this.lastName = "";
this.year = 0;
this.gpa = 0.0;
}

public StudentRecord(String firstName, String lastName, int year, double gpa) {
this.firstName = firstName;
this.lastName = lastName;
this.year = year;
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 int getYear() {
return year;
}

public void setYear(int year) {
this.year = year;
}

public double getGpa() {
return gpa;
}

public void setGpa(double gpa) {
this.gpa = gpa;
}
  
@Override
public String toString()
{
return ("First Name: " + getFirstName() + ", Last Name: " +
getLastName() + ", Year: " + getYear() + ", GPA: " + getGpa());
}

@Override
public int compareTo(StudentRecord record) {
int compare;
if(this.getGpa() < record.getGpa())
{
compare = -1;
}
else if(this.getGpa() > record.getGpa())
{
compare = 1;
}
else
compare = 0;
  
// if GPAs are equal
if(compare == 0)
{
compare = this.getYear() - record.getYear();
}
  
// if years are equal
if(compare == 0)
{
compare = this.getLastName().compareTo(record.getLastName());
}
  
// if last names are equal
if(compare == 0)
{
compare = this.getFirstName().compareTo(record.getFirstName());
}
return compare;
}
}

StudentRecordDriver.java (Client / Main class)

import java.util.ArrayList;
import java.util.Collections;

public class StudentRecordDriver {
  
public static void main(String[]args)
{
ArrayList<StudentRecord> studentRecords = new ArrayList<>();
studentRecords.add(new StudentRecord("Jes", "Reynaldsson", 1, 3.4));
studentRecords.add(new StudentRecord("Valeria", "Reynaldsson", 1, 3.7));
studentRecords.add(new StudentRecord("Valeria", "Reynaldsson", 1, 3.5));
studentRecords.add(new StudentRecord("Valeria", "Reynaldsson", 1, 3.68));
  
Collections.sort(studentRecords);
  
for(StudentRecord record : studentRecords)
{
System.out.println(record.toString());
}
}
}

un: First Name: Jes, Last Name: Reynaldsson, Year: 1, GPA: 3.4 First Name: Valeria, Last Nam Reynaldsson, Year 1, GPA: 3.5 First Name: Valeria, Last Nam Reynaldsson, Year: 1, GPA: 3.68 First Name: Valeria, Last Nam Reynaldsson, Year 1, GPA: 3.7 BUILD SUCCESSFUL (total time 0 seconds)

**********************************************************************************************************************************************

2.

import java.util.Scanner;

public class SelectionSortIntegers {
  
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.print("How many integers you want to enter? ");
int n = sc.nextInt();
  
int arr[] = new int[n];
  
System.out.println("Enter the integers: ");
for(int i = 0; i < n; i++)
{
arr[i] = sc.nextInt();
}
  
performSelectionSort(arr);
}
  
public static void performSelectionSort(int[] arr)
{
int n = arr.length;
for(int i = 0; i < n - 1; i++)
{
int minIndex = i;
for(int j = i + 1; j < n; j++)
{
if(arr[j] < arr[minIndex])
{
minIndex = j;
}
}
  
int temp = arr[minIndex];
arr[minIndex] = arr[i];
arr[i] = temp;
}
  
// print the sorted array
System.out.print("\nThe sorted array is: ");
for(int i = 0; i < arr.length; i++)
{
if(i == arr.length - 1)
System.out.print(arr[i] + "");
else
System.out.print(arr[i] + ", ");
}
System.out.println();
}
}

How many integers you want to enter? 5 Enter the integers: 10 The sorted array is 10, 22, 33, 44, 88 BUILD SUCCESSFUL (total time: 36 seconds)