Replace a #define by a method

[Marcelo]

Dear all,

I am a beginner of C/C++ programmation and I don't understand how the #define command works.

I would like to make this statement

#define MAX2(V1, V2) (V1>V2 ? V1 : V2)

as a C routine in order to use it in other C programs. However, I don't know what type to put for the retourning value.

Could you help me, please?

thanks a lot,

Marcelo

[Peter Jansson]

Marcelo wrote:

Dear all,

I am a beginner of C/C++ programmation and I don't understand how the
#define command works.

I would like to make this statement

#define MAX2(V1, V2) (V1>V2 ? V1 : V2)

as a C routine in order to use it in other C programs. However, I don't
know what type to put for the retourning value.

Could you help me, please?

thanks a lot,

Marcelo

Hello Marcelo,

#define is a pre-processor directive. Perhaps you want a normal
function, e.g.:
int MAX2(const int& V1, const int& V2)
{
return std::max(V1,V2);
}
with int replaced by the type you want, or perhaps a template?

Regards,
Peter Jansson

[David Harmon]

On Tue, 13 Dec 2005 22:47:17 +0100 in comp.lang.c++, Marcelo
<ma********@yahoo.com> wrote,

I am a beginner of C/C++ programmation and I don't understand how the #define command works.
Greetings. Since the answers are often different for C vs. C++ you
should make up your mind which one you want to use. In comp.lang.c++
it's C++.

#define works just as if the expanded text were written right into the
source at the point where it is invoked.
I would like to make this statement

#define MAX2(V1, V2) (V1>V2 ? V1 : V2)

as a C routine in order to use it in other C programs. However, I don't know what type to put for the retourning value.

In C++, you should use std::max().
The return type is the same as the argument type.

In C, the #define macro is passably OK and you can use it in multiple
programs by putting it in a header that you include, just as easily as
if it were a function. Beware of issues such as arguments with side
effects.

[Marcelo]

Marcelo wrote:

Dear all,

I am a beginner of C/C++ programmation and I don't understand how the
#define command works.

I would like to make this statement

#define MAX2(V1, V2) (V1>V2 ? V1 : V2)

as a C routine in order to use it in other C programs. However, I don't
know what type to put for the retourning value.

Could you help me, please?

thanks a lot,

Marcelo

Great ideas and explanations, thanks

[n2xssvv g02gfr12930]

Marcelo wrote:

Dear all,

I am a beginner of C/C++ programmation and I don't understand how the
#define command works.

I would like to make this statement

#define MAX2(V1, V2) (V1>V2 ? V1 : V2)

as a C routine in order to use it in other C programs. However, I don't
know what type to put for the retourning value.

Could you help me, please?

thanks a lot,

Marcelo

The STL libraries are based on templates and yes std::max() should fit
the bill. If you're likely to need generic classes and functions that
are based on specific types then I'd recommend you learn more about
template programming.

JB