Problems with inclusions.

Hi all,

I'm running into a pretty consistent problem doing inclusions with header files. I suspect the problem is that I don't fully understand what inclusions do, but if someone could give me a hand figuring it out?

Basically the problem is this. I have a header file and .cpp for a data type Planet, I also have a header file and .cpp for a data type Star. The header file for Star requires Planet to be included, as in it's constructer Star declares a vector of Planets.(I think this is the right way to do this?)

The problem arises with #ifndef and #define. Everything complies fine if I use #include "planet.h", but when I switch to #ifndef, it tells me that star is not an object. If I use #include"planet.h" then it compiles again. This is the code I'm using at the moment.

Code:

---

#ifndef PLANET_H
#define PLANET_H
#include <iostream>
#include <vector>
#include "planet.h"

---

Which compiles fine just so long as I leave the #include in there. But from what I was understanding, the #include shouldn't be necessary.

Where it gets worse, is for my main program I tell it...

Code:

---

#ifndef STAR_H
#define STAR_H
#ifndef PLANET_H
#define PLANET_H

---

And no matter what it tells me that star is

"error C2065: 'star' : undeclared identifier"

Even when I put in #include for star and planet.

Could anyone point me to what I'm doing wrong? If it helps any my header files...

planet- includes no .h files
star- includes planet.h
main- inludes star.h and planet.h

planet.cpp- includes only planet.h
star.cpp- includes only star.h

Any help is appriciated, I've tried reordering things till my minds gone kinda wonky...

Quote:

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But from what I was understanding, the #include shouldn't be necessary.

---

It is necessary, since planet.h is the file you want to include. Header guards are not a substitue for #include.

Your header files might be something like this:

Code:

---

// for planet.h
#ifndef PLANET_H
#define PLANET_H

// Planet related code

#endif

---

Code:

---

// for star.h
#ifndef STAR_H
#define STAR_H

#include "planet.h"

// Star related code

#endif

---

You only put the 'include guards' for a header around that header itself, NOT inside the files that will be including the header.

Ah!

Thank you! That explains it, Ty both :)