C 中的交叉引用结构

Question

有没有办法创建两个相互引用的结构？示例:

struct str1
{
  struct str1* ptr1;
  struct str2* ptr2;
}

struct str2
{
  struct str1* ptr1;
  struct str2* ptr2;
}

Answer 1

struct str2; // put a forward reference to str2 here

struct str1
{
  struct str1* s1;
  struct str2* s2;
};

struct str2
{
  struct str1* s1;
  struct str2* s2;
};

int main()
{
  struct str1 s1;
  struct str2 s2;

  s1.s1 = &s1;
  s1.s2 = &s2;
  s2.s1 = &s1;
  s2.s2 = &s2;

  return 0;
}