C++ #include guards

Question

SOLVED

What really helped me was that I could #include headers in the .cpp file with out causing the redefined error.

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I\'m new to C++ but I have some p

Answer 1

The goal of a header guard is to avoid including the same file many times. But the header guard that is currently used in C ++ can be improved. The current guard is:

#ifndef AAA_H
#define AAA_H

class AAA
{ /* ... */ };

#endif

My new guard proposal is:

#ifndef AAA_H
#define AAA_H

class AAA
{ /* ... */ };

#else
class AAA;  // Forward declaration
#endif

This resolves the annoying problem that occurs when the AAA class needs the BBB class declaration, while the BBB class needs the AAA class declaration, typically because there are crossed pointers from one class to the other:

// File AAA.h
#ifndef AAA_H
#define AAA_H

#include "BBB.h"

class AAA
{ 
  BBB *bbb;
/* ... */ 
};

#else
class AAA;  // Forward declaration
#endif

//+++++++++++++++++++++++++++++++++++++++

// File BBB.h
#ifndef BBB_H
#define BBB_H

#include "AAA.h"

class BBB
{ 
  AAA *aaa;
/* ... */ 
};

#else
class BBB;  // Forward declaration
#endif

I would love for this to be included in the IDEs that automatically generate code from templates.