Question

This is a Java text only program. This program will ask if the user wants to create a music playlist. If user says he or she would like to create this playlist, then the program should first ask for a name for the playlist and how many songs will be in the playlist. The user should be informed that playlist should have a minimum of 3 songs and a maximum of 10 songs. Next, the program will begin a loop to allow the user to enter the song information for the specified number of songs. The user should be asked to enter the name of the song, the artist, the song duration, and the song genre, for example Pop, Rock, Rap, Country, Hip-Hop, Jazz, Classical, Foreign Songs. After all of the songs have been entered, the program should display a list of all of the information and ask which or if any of the entries need to be corrected. If the user indicates a particular song, then the program should let the user re-enter and replace the data for that particular song. If the user indicates that no songs need to be corrected, then the program will display the final list of songs that are displayed, it should also show the total duration of the playlist, a count of songs in each genre, and the average song duration.

Answer 1

The screenshots of Java code for the given problem (copyable code also included below) are:

Although the code is well-commented and all the variables used are self-explanatory, here is a brief explanation of the code:

• To store all the information of the song, a separate class called "song" is being made. It contains a method to add a song (i.e., to initialize the data members or properties like name, artist, etc. of the song), getter methods that return genre and duration (as they are needed in the main() method), and a method that displays the song info.
• In the main() method, the program first asks if the user wants to create a playlist. If not, then the program ends.
• If yes, then the program asks for the name of the playlist and the number of songs to be added in the playlist.
• Then, an array of objects of the Song class is made with size equal to the number of songs. Each object will represent a particular song.
• One by one, all the objects are initialized inside a for loop.
• After adding all the songs, the final list is displayed. The program then asks the user if any of the entries need to be corrected. If not, then the above displayed list is the final list.
• If yes, then the user is asked the number of the particular song that needs to be modified. Then, the new information for that song is asked from the user and the final list after modification is displayed on the screen.
• Now is the time when we will need the duration and genre of each song to calculate the total duration, average duration, and number of songs in each genre (genre count).
• To get the duration and genre for each song, we will use the getDuration() and getGenre() methods of the Song class. This is why we created them in the first place.
• For finding out the genre count, a hashmap is used with the genre names as the keys and the number of songs of that genre as its value.
• All the calculated values are finally displayed.

The copyable code is given below:

import java.util.*;

class Song

{

String name, artist, genre;

int duration; //in seconds

public void addSong()

{

Scanner sc = new Scanner(System.in);

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

name = sc.nextLine();

System.out.print("Artist: ");

artist = sc.nextLine();

System.out.print("Duration (in seconds): ");

duration = sc.nextInt();

System.out.print("Genre: ");

genre = sc.next();

}

public String getGenre()

{

return genre;

}

public int getDuration()

{

return duration;

}

public void displaySongInfo()

{

System.out.println("Name: " + name);

System.out.println("Artist: " + artist);

System.out.println("Duration (seconds): " + duration);

System.out.println("Genre: " + genre);

}

}

public class Main

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

int n; //number of songs

String playlist; //name of the playlist

char choice; //variable to indicate "Yes" or "No" entered by user

System.out.print("Do you want to create a playlist? (Y/N) ");

choice = sc.next().charAt(0);

if(choice=='Y' || choice=='y')

{

System.out.print("Enter a name for the playlist: ");

playlist = sc.next();

System.out.print("How many songs do you want in the playlist (min 3 max 10)? ");

n = sc.nextInt();

Song s[] = new Song[n]; //n objects of Song class, one for each song

for(int i=0; i<n; i++)

{

System.out.println("\nEnter the information for song " + (i+1));

s[i] = new Song();

s[i].addSong();

}

System.out.println("\nAll the songs added successfully.");

System.out.println("Here is the list of them: ");

//Displaying all the songs

for(int i=0; i<n; i++)

{

System.out.println("\nSong " + (i+1));

s[i].displaySongInfo();

}

System.out.print("\nDo you want to modify any song info? (Y/N) ");

choice = sc.next().charAt(0);

if(choice=='Y' || choice=='y') //Modify a particular song

{

System.out.print("Enter the song number that you want to modify: ");

int songNumber = sc.nextInt();

System.out.println("Here is the information for song " + songNumber);

s[songNumber-1].displaySongInfo();

System.out.println("\nEnter the new information for song " + songNumber);

s[songNumber-1].addSong();

System.out.println("Song modified successfully! The final playlist is:");

for(int i=0; i<n; i++)

{

System.out.println("\nSong " + (i+1));

s[i].displaySongInfo();

}

}

else //When the user doesn't want to modify any song

{

System.out.println("Okay! So the above playlist is final.");

}

int totalDuration = 0; //Total Duration of the playlist

double avgDuration; //Average song duration

for(int i=0; i<n; i++)

totalDuration += s[i].getDuration();

avgDuration = (double)totalDuration / (double)n;

System.out.println("\nThe total duration of the playlist is " + totalDuration + " seconds.");

System.out.println("Average song duration = " + avgDuration + " seconds");

HashMap<String, Integer> genreCount = new HashMap<>(); //To store the count of each genre

String genre;

for(int i=0; i<n; i++)

{

genre = s[i].getGenre(); //Genre of current song

if(genreCount.containsKey(genre))

genreCount.replace(genre, genreCount.get(genre)+1); //If present, increment count

else

genreCount.put(genre, 1); //If not present, insert, with count 1

}

System.out.println("Number of songs in each genre:");

System.out.println(genreCount);

}

sc.close();

}

}

The screenshots of the output are:

Hope it helped. If you have any doubts or queries, please feel free to ask in the comments section. If it helped in any way, please consider giving a thumbs up as it takes a lot of time and effort to write such detailed answers.