Is this valid?

[Michael]

Hi i recently came across some code that looked like this which I've never
ever seen before! I appreicate it may be 'c' but is it valid in c++??


//main.c

int main()
{
int a;
int b;
//Get values for a & b;

if(a==1)
{
#include "DoA.c"
}
else
{
#include "DoB.c"
}

// More stuff


return 0;
}


//DoA.c
b =4;


//DoB.c
b=6;



Is this valid? Or just obscure?

[Matt Wharton]

Re: Is this valid?

"Michael" <slick_mick_00@ hotmail.com> wrote in message
news:clp7u1$dje $1@sparta.btint ernet.com...[color=blue]
> Hi i recently came across some code that looked like this which I've never
> ever seen before! I appreicate it may be 'c' but is it valid in c++??
>
>
> //main.c
>
> int main()
> {
> int a;
> int b;
> //Get values for a & b;
>
> if(a==1)
> {
> #include "DoA.c"
> }
> else
> {
> #include "DoB.c"
> }
>
> // More stuff
>
>
> return 0;
> }
>
>
> //DoA.c
> b =4;
>
>
> //DoB.c
> b=6;
>
>
>
> Is this valid? Or just obscure?
>
>[/color]

Yes, it's valid. Yes, it's obscure (and entirely unnecessary in the example
you posted).

-Matt

[Ioannis Vranos]

Re: Is this valid?

Michael wrote:
[color=blue]
> Hi i recently came across some code that looked like this which I've never
> ever seen before! I appreicate it may be 'c' but is it valid in c++??
>
>
> //main.c
>
> int main()
> {
> int a;
> int b;
> //Get values for a & b;
>
> if(a==1)
> {
> #include "DoA.c"
> }
> else
> {
> #include "DoB.c"
> }
>
> // More stuff
>
>
> return 0;
> }
>
>
> //DoA.c
> b =4;
>
>
> //DoB.c
> b=6;
>
>
>
> Is this valid? Or just obscure?[/color]


It is valid.



--
Ioannis Vranos

http://www23.brinkster.com/noicys

[Michael]

Re: Is this valid?

in that case, does #include mean copy contents of file here ( with the
absence of pragma's)?

"Matt Wharton" <noSpam@noSpam. com> wrote in message
news:1098916940 .753896@cswreg. cos.agilent.com ...[color=blue]
> "Michael" <slick_mick_00@ hotmail.com> wrote in message
> news:clp7u1$dje $1@sparta.btint ernet.com...[color=green]
> > Hi i recently came across some code that looked like this which I've[/color][/color]
never[color=blue][color=green]
> > ever seen before! I appreicate it may be 'c' but is it valid in c++??
> >
> >
> > //main.c
> >
> > int main()
> > {
> > int a;
> > int b;
> > //Get values for a & b;
> >
> > if(a==1)
> > {
> > #include "DoA.c"
> > }
> > else
> > {
> > #include "DoB.c"
> > }
> >
> > // More stuff
> >
> >
> > return 0;
> > }
> >
> >
> > //DoA.c
> > b =4;
> >
> >
> > //DoB.c
> > b=6;
> >
> >
> >
> > Is this valid? Or just obscure?
> >
> >[/color]
>
> Yes, it's valid. Yes, it's obscure (and entirely unnecessary in the[/color]
example[color=blue]
> you posted).
>
> -Matt
>
>[/color]

[Jonathan Turkanis]

Re: Is this valid?


"Michael" <slick_mick_00@ hotmail.com> wrote in message
news:clpffo$k93 $1@titan.btinte rnet.com...[color=blue]
> in that case, does #include mean copy contents of file here ( with the
> absence of pragma's)?[/color]

It means exactly the same thing as it does when used at the beginning of a file.
The preprocessor knows nothing about control structures such as if ( ) { }else
{ }, and so has no idea that headers are being #include'd in unusual places.

The ability to #include headers in the middle of a block of code is very useful
for preprocess metaprogramming (see
http://boost-consulting.com/tmpbook/preprocessor.html)

Jonathan

[Ioannis Vranos]

Re: Is this valid?

Michael wrote:
[color=blue]
> in that case, does #include mean copy contents of file here ( with the
> absence of pragma's)?[/color]


#includes are processed by the preprocessor before the compilation. In
the final source code that gets compiled, the #includes have been
replaced by the text that they include.



--
Ioannis Vranos

http://www23.brinkster.com/noicys