How do I merge linked list alternately without using nodes? and by using recursion?

Question

There are no errors but it still won't work. I can't figure out what's wrong. We still haven't discussed the concept of nodes in class so I have trouble understanding it.

It's output should be:

Skinny Love- Birdy

Happier- Ed Sheeran

Someday- Chelsea Cutler

public class HandsOnAct1 {

  static LinkedList songs = new LinkedList();
  static LinkedList artists = new LinkedList();
  static LinkedList playlist = new LinkedList();
  
  public static void Merge(){
      int element= songs.size();
      int number=0;
      
      System.out.println(element);
      
  if (number !=element){
  playlist.add(number, songs);
  playlist.add(number,artists);
  number++;
  
  }
      System.out.println(playlist);
  }
  

    public static void main(String[] args) {
 
        songs.add("Skinny Love");
        songs.add("Happier");
        songs.add("Sometimes");
        
        artists.add("Birdy");
        artists.add("Ed Sheeran");
        artists.add("Chelsea Cutler");
        
        Merge();    
    }
    
}

Answer 1

Here is an example using recursion as i understand it was a pre-requisite?

static LinkedList<String> songs = new LinkedList<>();
static LinkedList<String> artists = new LinkedList<>();
static LinkedList<String> playlist = new LinkedList<>();

songs.add("Skinny Love");
songs.add("Happier");
songs.add("Sometimes");

artists.add("Birdy");
artists.add("Ed Sheeran");
artists.add("Chelsea Cutler");

int index = 0;
static void merge() {

    // if you want/need checks
    if ( index >= artists.size()){
        return;
    }

    playlist.add(songs.get(index) + " - " + artists.get(index));
    System.out.println(playlist.get(index));
    index++;
    merge();
}

merge();

the main issue with your own code is that you need to call merge again from inside it and either move the index outside the function as i have done or take it in as a parameter like public static void merge(int index) . you will then call it from inside like merge(index++) .

That's a matter of opinion i guess. (if you want you can read on pure/impure functions and imperative/functional programming which is the difference)