结构内部的struct数组

Question

why can't i do this:

 typedef struct _word{
      struct _word ws[ 28 ];
 }Word;

With the code above i'm get the error: field 'ws' has incomplete type.

Why can i do just this:

 typedef struct _word{
      struct _word *wr[ 28 ];
 }Word;

I want static memory.

Answer 1

Because if your structure is not completely defined, you can't calculate the size of the object to be allocated. As others mentioned, it'll be an infinite regression trying to deduce the size of the object.

But you can always calculate the size of a pointer. Hence the 2nd version works.