Added comments

src/main.rs

@@ -11,12 +11,14 @@ struct Playlist{
 }
 
 impl Playlist{
+    // Empty constructor
     fn new() -> Playlist {
         Playlist{
             songs: Vec::new(),
         }
     }
 
+    // Generates iterator from playlist
     fn iter(&self) -> PlaylistIterator{
         PlaylistIterator{
             playlist: self,
@@ -24,6 +26,7 @@ impl Playlist{
         }
     }
 
+    // Adds a song to playlist
     fn add_song(&mut self, song: Song){
         self.songs.push(song);
     }
@@ -38,15 +41,22 @@ impl<'a> Iterator for PlaylistIterator<'a>{
     type Item = &'a Song;
 
     fn next(&mut self) -> Option<Self::Item> {
+        // Attempts to get current song
         let song = self.playlist.songs.get(self.current_index as usize);
+
+        // Moves id to next song
         self.current_index += 1;
+
+        // Returns song or nothing
         song
     }
 }
 
 fn main() {
+    // Creating a playlist
     let mut playlist = Playlist::new();
 
+    // Adding songs to a playlist
     playlist.add_song(
         Song{
             name: String::from("s1"),
@@ -69,6 +79,7 @@ fn main() {
         }
     );
 
+    // Iterating over playlist and printing song information
     for song in playlist.iter(){
         println!("{:?}", song);
     }