c - C 中另一个结构体内部的结构体

Question

这个问题已经有答案了:

self referential struct definition? (9 个回答)

Why can't a struct be a member of itself? (3 个回答)

已关闭 7 年前。

我需要做这样的事情:

typedef struct a A;
typedef struct b B;


struct a{
    B oi;
};

struct b{
    A ola;
};

但是当我尝试编译时它返回此错误:

gustavo@depaula-ubuntu:~/Desktop/grafo$ gcc test.c 
test.c:3:12: error: field ‘ola’ has incomplete type
   struct a ola;
            ^

编辑:我不认为这是一个 XY 问题，但我需要上面的代码(它不起作用):

typedef struct union util;
typedef struct graph Graph;
typedef struct vertex_struct Vertex;
typedef struct arc_struct Arc;

typedef struct graph{
    Vertex * vertices;
} Graph;

typedef struct vertex_struct {
    struct arc_struct * arcs;
    int name;
    struct util u, v, w, x, y, z;
};

typedef struct arc_struct {
    struct vertex_struct * tip;
    struct arc_struct * next;
    struct util a, b;
};

struct union {
    struct vertex_struct * V;
    struct arc_struct * A;
    struct graph_struct * G;
    char * S;
    int I;
};

Answer 1

你无法做你正在尝试的事情。

其中一个成员必须是指针。

struct a{
    B* oi;
};

struct b{
    A ola;
};

或

struct b{
    A* ola;
};

struct a{
    B oi;
};