Question

I’m working on a DnD-Text-Based-Style C game, and I’m having a problem compiling my structure.
Here is what I have for a structure so far:

typedef struct stats {                  //
    int strength;               //
    int wisdom;                 //
    int agility;                //
} stats;

typedef struct rooms {
    int n_monsters;
    int visited;
    rooms nentry;
    rooms sentry;
    rooms wentry;
    rooms eentry;
    monster *monsters;
} rooms;

typedef struct monster {
    int difficulty;
    char *name;
    char *type;
    int hp;
} monster;

typedef struct dungeon {
    char *name;
    int n_rooms;
    rooms *rooms;
} dungeon;

typedef struct player {
    int maxhealth;
    int curhealth;
    int mana;
    char *class;
    char *condition;
    stats stats;
    rooms c_room;
} player;

typedef struct game_structure {
    player p1;
    dungeon d;
} game_structure;

When I compile it, I get the error:
structure.h:21: error: specifier-qualifier-list before ‘rooms’

Can you help me figure out why this is? Is it because I’m calling rooms from the structure that contains rooms? Please help.

Answer 1

There are many many problems with this piece of code. The first is that a struct definition must know how much memory to allocate, and it cannot do this when it contains a type that has not been fully defined (this is why people recommend that you use a pointer, since the size of a pointer is known at compile time).

However, and this is important, simply changing to pointers will not solve the problem, since the first room* is encountered before the appropriate typedef completes. You would need to write something like:

struct rooms {
    int n_monsters;
    int visited;
    struct rooms *nentry;
    struct rooms *sentry;
    struct rooms *wentry;
    struct rooms *eentry;
    monster *monsters;
} rooms;

or perform a forward declaration (typedef struct rooms rooms;). You also need to make sure the monster type is defined or at least has a forward declaration.