.h or .cpp

Applications Programming
1

I have the code below and cannot decide if to put it in a .h file or in a .cpp file

#ifndef VERBOSE_H
#define VERBOSE_H

#include "sstring.h"

enum Verbose { none = 0, low = 1, medium = 2, high = 3, diag = 4 };

bool  GetVerbose(String&  S, Verbose&  V) {
  S.ToUpper();
  if (S == String("NONE")) { V = none; return (true); }
  if (S == String("LOW")) { V = low; return (true); }
  if (S == String("MEDIUM")) { V = medium; return (true); }
  if (S == String("HIGH")) { V = high; return (true); }
  if (S == String("DIAG")) { V = diag; return (true); }
  return (false);
}

#endif
2

That will cause duplicate symbol errors if you include that file in multiple .cpp files because you'd declare the same function body over and over.

I'd change it to this:

#ifndef VERBOSE_H
#define VERBOSE_H

#include "sstring.h"

enum Verbose { none = 0, low = 1, medium = 2, high = 3, diag = 4 };

extern bool  GetVerbose(String&  S, Verbose&  V);
#endif

Put the function body in one and only one .cpp file.

Alternatively, you could make it an inline function, which would prevent it from having a symbol definition at all.

3

Thank you. If I include it inline, I would not need to have a .cpp file then. Is that right? Is it ok not to have a .cpp on some occasions like this one?

---------- Post updated at 05:02 AM ---------- Previous update was at 04:45 AM ----------

I had originally some code concerning a class (definition and implementation) in a header file put have now split it to have the definition and inline functions in the .h file, and the rest of the implementation in a .ccp file.

This is what I have for the .cpp file

The #ifndef, #define, #include and #endif were in the .h file. Should I remove them from the .cpp file as well, as to your explanation?

#ifndef COMPLEX_H
#define COMPLEX_H

#include <assert.h>
#include <cmath>
#include <iostream>

#include "gendef.h"

//////////////////////////////////////////////////////////////////////////

Complex&  Complex:operator /= (const Complex&  C) {
  assert((C.Re != 0) || (C.Im != 0));
  REAL  mod = (C.Re * C.Re) + (C.Im * C.Im);
  REAL  nr, ni;
  nr = ( (Re * C.Re) + (Im * C.Im) ) / mod;
  ni = ( (C.Re * Im) - (Re * C.Im) ) / mod;
  Re = nr;
  Im = ni;
  return (*this);
}

#endif
4

Those #ifndef/#define/#endif don't belong there, no. That arrangement is to prevent a .h file from being included more than once -- if you accidentally do so, FILE_H will already be defined and the preprocessor will harmlessly skip over the contents.

The string is completely arbitrary, by the way. You could have #ifndef SLARTIBARTFAST and it would work, as long as SLARTIBARTFAST is only used for one .h file.