C字段的类型不完整

Question

我有以下头文件：

 #ifndef SERVER_STRUCTURES_H
 #define SERVER_STRUCTURES_H

typedef struct game {
  int id;
  struct player player1;
  struct player player2;
  struct game *next;
} game_t;

typedef struct player {
  int id;
  int score;
  struct player *player1;
  struct game *g ;
} player_t;

#endif

我收到错误：字段'player1'具有不完整的类型struct player player1

和

字段'player2'具有不完整的类型struct player player2。

怎么了？谢谢！

Answer 1

声明必须在使用它们的位置之前，因此应交换两个声明。要分配player1和player2，编译器将要求完整声明struct player。

然后，您应该告诉编译器以后将声明struct game。这足以创建“指向某物的指针”。

#ifndef SERVER_STRUCTURES_H
#define SERVER_STRUCTURES_H

struct game;

typedef struct player {
  int id;
  int score;
  struct player *player1;
  struct game *g ;
} player_t;

typedef struct game {
  int id;
  struct player player1;
  struct player player2;
  struct game *next;
} game_t;

#endif