Java Programming: Mutator Method Assignment Q&A

On paper, write a method called sum with a while loop that adds up all numbers between two numbers a and b, inclusive, and returns the sum as its result. The values for a and b can be passed to the sum method as parameters. For instance: sum(1, 5) would return the value 15 (i.e., 1 + 2 + 3 + 4 + 5).

What happens if the value of the second parameter is less than the value of the first?

public int Sum (int a, int b) {
int sum = 0;
while (a < b) {
sum += a;
Sum += b;
return sum ;

Exercise 4.37
[Assessment 2(17): You must have this exercise signed off by your class supervisor] Add a further field, of your choosing, to the Track class, and provide accessor and mutator methods to query and manipulate it. Find a way to use this information in your version of the project; for instance, include it in a track’s details string, or allow it to be set via a method in the MusicOrganizer class.

Public Music organizer ()
Track = new Arraylist ();
Player = new Music player ();
Reader = new TrackReader ();
Edit = new EditTrack ();
Read Library (“audio”);
Systems.out.println (“Music library loaded.” + get Number of Track + “tracks.”); System.out.println();
Public void edit Track (track)
Trackedit (track);

Exercise 4.43
[Assessment 2(18): You must have this exercise signed off by your class supervisor] The java.util package contains the Random class whose nextInt method will generate a positive random integer within a limited range. Write a method in the MusicOrganizer class to select a single random track from its list and play it.

Hint: You will need to import Random and create a Random object, either directly in the new method or in the constructor and stored in a field. You will need to find the API documentation for the Random class and check its methods to choose the correct version of nextInt.

Import java. Util Random;
//random generator
Private Random rand;
rand = new Random();
public void play randomtrack
Int randomNumber = rand.Nextln (track.size());