Question

Will p = (users *)malloc(sizeof(users)); create memory for the playlist structure too? Also how can I reference playlist.album using p?

struct playlist_ {
  int album;
  int track_num;
  struct playlist_ *next;
};

struct users_ {
  int user_ID;
  struct playlist_ playlist;
  struct users_ *next;
};

typedef struct playlist_  playlists;
typedef struct users_ users;

users *p;
p = (users *)malloc(sizeof(users));

Answer 1

Will p = (users *)malloc(sizeof(users)); create memory for the playlist structure too?

playlist is a member of users_, so it forms part of the allocated space. So to answer your question: yes.

[Incidentally, you don’t need to (and shouldn’t) cast the result of malloc.]

Also how can I reference playlist.album using p?

Depends what you mean by “reference”. Assuming you just mean “access”, then this:

p->playlist.album