code problem

I am trying to do insertion sort with list (ADT), I wrote the function InsertionSortList in the sort.c file:

Code:

void
InsertionSortList(List L)
{
  Position P1, P2;
  ElementType temp;
  for(P1 = L; P1->Next != NULL; P1 = P1->Next)  //problem
    {
      temp = P1->Element; //problem
      for(P2 = P1; (P2->Last != NULL) && (P2->Last->Element < P2->Element); P2 = P2->Last) //problem
	P2->Element = P2->Last->Element; //problem
    }
}

while i am compling my programme, the gcc complier said:
dereferencing pointer to incomplete type
these problems happend at the lines which I indicate in the function

How can I deal with it? Thx a lot!

The sort.c file, may be useful.

can you post the headers "fatal.h" and "list.h". I have a feeling that you have just declared the structures but haven't actually defined them.

ie. You told the compiler a structure name but haven't given any body to that name.

list.c

list.h

yup, this code

Code:

 /* Place in the interface file */
        struct Node
        {
            ElementType Element;
            Position    Next;
	    Position    Last;
        };

is in list.c

put it into list.h

could you tell me where shold I put it in list.h?
thx

in list.h

the line

Code:

struct Node;

replace it with the structure body.

thank you!