Extern and CLASS

dannygilbert3

Easy question but I don't find the answer.:sigh: I have a header file with some classes. These classes used some class from one another header file. How can I tell to compiler to use the classes from other header files ? Extern does not work, only work on object.

Danny Gilbert Montréal, Canada

Mark Salsbery

dannygilbert3 wrote:

How can I tell to compiler to use the classes from other header files ?

#include "OtherHeaderFile.h"

toxcct

#include is the directive for you...

You don't know where to start ? ask a good friend

[VisualCalc 3.0][Flags Beginner's Guide]

James R Twine

If you only need to declare pointers or references to those other classes, you can do a forward declaration (I believe that is what it is called) by putting code like this:

class CClass;
class CSomeOtherClass;

Before the code that declare pointers/references to that class.

class CClass;
class CSomeOtherClass;

class CMyClass
{
   public:
   CMyClass( CClass *pClass );
   CMyClass( CSomeOtherClass &socSomeOtherClass );
   CMyClass( CAnotherClass *pAnotherClass );     // This One Will Not Compile
   CMyClass( CAnotherClass &cacAnotherClass );   // This One Will Not Compile
};

If you need to actually access members of the class, then you need to include the entire declaration of the class (usually by including its .H file). This is usually required in the CPP file for the class that uses the other classes. Be careful throwing includes around freely if you are not fully familiar with the code, you can introduce dependency problems and/or mess up your build times. Peace!

-=- James

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