在结构中声明一个结构？

Question

我正在开发一个简单的程序，根据地图在房子里创建房间。对于每个房间，我列出连通房间。问题是，这无法编译。知道为什么吗？

typedef struct s_room {
    char *name;
    int nbr;
    int x;
    int y;
    bool start;
    bool end;
    int ants;
    int current;
    t_room *connect;
    int visited;

} t_room;

我认为它来自t_room *connect，但我无法弄清楚如何解决这个问题。

Answer 1

替换

typedef struct      s_room
{
    ....
    t_room          *connect;
    ....
}                   t_room;

与

typedef struct      s_room
{
    ....
    struct s_room   *connect;
    ....
}                   t_room;

Answer 2

两个选项：

1. 类型

   的转发声明

   typedef struct      s_room t_room;
   struct s_room {
       t_room          *connect;
   };
   

2. 使用struct s_room

   typedef struct s_room {
       struct s_room  *connect;
   } t_room;
   

Answer 3

您不能使用结构类型t_room来定义类型t_room本身，因为它尚未定义。因此，您应该替换此

t_room *connect;

与

struct s_room *connect;

或者您可以在实际定义typedef之前输入struct s_room struct s_room。然后，您可以在定义中使用类型别名。

// struct s_room type is not defined yet.
// create an alias s_room_t for the type.

typedef struct s_room s_room_t; 

// define the struct s_room type and
// create yet another alias t_room for it.

typedef struct s_room {
    // other data members
    s_room_t *connect; 

    // note that type of connect is not yet defined
    // because struct s_room of which s_room_t is an alias
    // is not yet fully defined.

} t_room;

// s_room_t and t_room are both aliases for the type struct s_room

就个人而言，我更喜欢前者，因为要做后者，你必须引入一个额外的typedef来定义另一个typedef！这看起来像名称空间混乱，没有任何实际好处。