How to properly name include guards in c++

Question

I have 3 header files:

misc.h
MyForm.h
Registration.h

In misc.h file I put

#ifndef MISC_H
#define MISC_H
#endif

Answer 1

You should use include guards in every header file and nothing should be outside the include guards.

The name of include guards can be anything as long as it is unlikely to clash with any other name. An example for your MyForm.h might be:

#ifndef MYFORM_HEADER_
#define MYFORM_HEADER_

#include "misc.h"
#include "Registration.h"

/* all code here */

#endif

It is also important that nothing is written outside of the include guards in a header file.