Question

JAVA PROGRAMMING

Given main(), complete the SongNode class to include the printSongInfo() method. Then write the Playlist class' printPlaylist() method to print all songs in the playlist. DO NOT print the dummy head node.

Ex: If the input is:

Stomp!
380
The Brothers Johnson
The Dude
337
Quincy Jones
You Don't Own Me
151
Lesley Gore
-1

the output is:

LIST OF SONGS
-------------
Title: Stomp!
Length: 380
Artist: The Brothers Johnson

Title: The Dude
Length: 337
Artist: Quincy Jones

Title: You Don't Own Me
Length: 151
Artist: Lesley Gore

SongNode.java sample code:

public class SongNode {
private String songTitle;
private int songLength;
private String songArtist;
private SongNode nextNodeRef; // Reference to the next node   

public SongNode() {
songTitle = "";
songLength = 0;
songArtist = "";
nextNodeRef = null;
}

// Constructor   
public SongNode(String songTitleInit, int songLengthInit, String songArtistInit) {
this.songTitle = songTitleInit;
this.songLength = songLengthInit;
this.songArtist = songArtistInit;
this.nextNodeRef = null;
}

// Constructor   
public SongNode(String songTitleInit, int songLengthInit, String songArtistInit, SongNode nextLoc) {
this.songTitle = songTitleInit;
this.songLength = songLengthInit;
this.songArtist = songArtistInit;
this.nextNodeRef = nextLoc;
}

// insertAfter
public void insertAfter(SongNode nodeLoc) {
SongNode tmpNext;

tmpNext = this.nextNodeRef;
this.nextNodeRef = nodeLoc;
nodeLoc.nextNodeRef = tmpNext;
}

// Get location pointed by nextNodeRef
public SongNode getNext() {
return this.nextNodeRef;
}

// TODO: Write printSongInfo() method
  
}

Playlist.java sample code:

import java.util.Scanner;

public class Playlist {

public static void printPlaylist(SongNode songs){
SongNode song = songs.getNext();
while (song!=null) {
song.printSongInfo();
System.out.println();
song = song.getNext();
}
}

public static void main (String[] args) {
Scanner scnr = new Scanner(System.in);

SongNode headNode;
SongNode currNode;
SongNode lastNode;

String songTitle;
int songLength;
String songArtist;

// Front of nodes list
headNode = new SongNode();
lastNode = headNode;

// Read user input until -1 entered
songTitle = scnr.nextLine();
while (!songTitle.equals("-1")) {
songLength = scnr.nextInt();
scnr.nextLine();
songArtist = scnr.nextLine();

currNode = new SongNode(songTitle, songLength, songArtist);
lastNode.insertAfter(currNode);
lastNode = currNode;

songTitle = scnr.nextLine();
}
  
// Print linked list
System.out.println("LIST OF SONGS");
System.out.println("-------------");
printPlaylist(headNode);
}
}

Answer 1

The printSongInfo method could be written as:

public void printSongInfo()
   {
           System.out.println("Title: "+this.songTitle);
           System.out.println("Length: "+this.songLength);
           System.out.println("Artist: "+this.songArtist);
   }

The output of the code :

Whole Code for the reference:

SongNode.java

public class SongNode {
   private String songTitle;
   private int songLength;
   private String songArtist;
   private SongNode nextNodeRef; // Reference to the next node   

   public SongNode() {
   songTitle = "";
   songLength = 0;
   songArtist = "";
   nextNodeRef = null;
   }

   // Constructor   
   public SongNode(String songTitleInit, int songLengthInit, String songArtistInit) {
       this.songTitle = songTitleInit;
       this.songLength = songLengthInit;
       this.songArtist = songArtistInit;
       this.nextNodeRef = null;
   }

   // Constructor   
   public SongNode(String songTitleInit, int songLengthInit, String songArtistInit, SongNode nextLoc) {
       this.songTitle = songTitleInit;
       this.songLength = songLengthInit;
       this.songArtist = songArtistInit;
       this.nextNodeRef = nextLoc;
   }

   // insertAfter
   public void insertAfter(SongNode nodeLoc) {
       SongNode tmpNext;

       tmpNext = this.nextNodeRef;
       this.nextNodeRef = nodeLoc;
       nodeLoc.nextNodeRef = tmpNext;
   }

   // Get location pointed by nextNodeRef
   public SongNode getNext() {
       return this.nextNodeRef;
   }

   // TODO: Write printSongInfo() method
   public void printSongInfo()
   {
           System.out.println("Title: "+this.songTitle);
           System.out.println("Length: "+this.songLength);
           System.out.println("Artist: "+this.songArtist);
   }
  
  
}

Playlist.java

import java.util.Scanner;

public class Playlist {

   public static void printPlaylist(SongNode songs){
       SongNode song = songs.getNext();
       while (song!=null) {
           song.printSongInfo();
           System.out.println();
           song = song.getNext();
       }
   }

   public static void main (String[] args) {
       Scanner scnr = new Scanner(System.in);

       SongNode headNode;
       SongNode currNode;
       SongNode lastNode;

       String songTitle;
       int songLength;
       String songArtist;

       // Front of nodes list
       headNode = new SongNode();
       lastNode = headNode;

       // Read user input until -1 entered
       songTitle = scnr.nextLine();
       while (!songTitle.equals("-1")) {
       songLength = scnr.nextInt();
       scnr.nextLine();
       songArtist = scnr.nextLine();

       currNode = new SongNode(songTitle, songLength, songArtist);
       lastNode.insertAfter(currNode);
       lastNode = currNode;

       songTitle = scnr.nextLine();
       }
      
       // Print linked list
       System.out.println("LIST OF SONGS");
       System.out.println("-------------");
       printPlaylist(headNode);
   }
}