有关指针的前向参考？

Question

  

可能重复：
  What is forward reference in C?

我在某处读到了这个问题

"What is forward reference with respect to pointers in C, and what are its advantages"

此处提到的接受答案：What is forward reference in C? 没有给出正确的解释？ 任何人都可以解释它究竟意味着什么它有什么优势吗？

Answer 1

前向引用wrt指针是我们使用的术语，

声明指针，编译器为指针保留内存，但未定义指针指向的DataItem。

来自之前的答案::

struct MyStruct *ptr; // this is a forward reference cuz pointer ptr is declared
                      // but the structure it points to is itself not defined till now.

struct MyStruct // Now the structure is declared
{
       // some data members
};

优点:: Advantages