Question

We have an assignment in school where we got a header file and we
need to implement it. The header defines:

typedef struct Board* BoardP;

which to my understanding means the BoardP is a pointer to struct Board.
Anyhow, my implementation is:

typedef struct Board
{
    int width;
    int height;
    char *board;
} *BoardP;

But i keep getting:

Board.c:21: error: redefinition of typedef ‘BoardP’
Board.h:4: note: previous declaration of ‘BoardP’ was here

Any ideas as to why this happens? Thanks!

EDIT: another question. As you can see my struct hold an array of characters. When I write a constructor should I initialize (malloc(sizeof(height*width)) the array first and then the struct? And how about use of free()? Should I free the array first and then the struct?
Thanks

Answer 1

Drop the typedef from the definition.

struct Board
{
    int width;
    int height;
    char *board;
};

A struct is a struct; it’s not like you always have to typedef it. To be honest, I only typedef structs for opaque pointers.

From style(9):

Avoid using typedefs for structure types. Typedefs are problematic
because they do not properly hide their underlying type; for example
you need to know if the typedef is the structure itself or a pointer
to the structure. In addition they must be declared exactly once,
whereas an incomplete structure type can be mentioned as many times as
necessary.