DaniWeb Forum Index > Software Development > C++

How do you write a code which compiles in c but not in c++?

Please support our C++ advertiser: Programming Forums - DaniWeb Sister Site

•

Join Date: May 2004

Posts: 4

Reputation: prabhu_kar is an unknown quantity at this point

Solved Threads: 0

prabhu_kar prabhu_kar is offline

Offline

Newbie Poster

How do you write a code which compiles in c but not in c++?

May 6th, 2004

How am i supposed to write a code in c which compiles in c but not in c++
plz do let me know

•

Join Date: Mar 2004

Posts: 77

Reputation: infamous is an unknown quantity at this point

Solved Threads: 2

infamous

Offline

Junior Poster in Training

Re: How do you write a code which compiles in c but not in c++?

May 6th, 2004

c++ is a subset of c, or maybe it's the otehr way round i 4got that crap, but anyhow, piont is, u can't.

•

Join Date: May 2004

Posts: 141

Reputation: meabed is on a distinguished road

Solved Threads: 3

meabed

Offline

Junior Poster

Re: How do you write a code which compiles in c but not in c++?

May 6th, 2004

This Right YOu can't do that coz C is subset of C++ ...

•

Join Date: Apr 2004

Posts: 4,461

Reputation: Dave Sinkula has a brilliant future

Solved Threads: 254

Dave Sinkula Dave Sinkula is offline

Offline

long time no c

Re: How do you write a code which compiles in c but not in c++?

May 6th, 2004

>How am i supposed to write a code in c which compiles in c but not in c++

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <stdio.h>
 
int main(void)
{
char new[] = "Compiles in C, not in C++";
puts(new);
return 0;
}
#include <stdio.h>
 
int main(void)
{
char new[] = "Compiles in C, not in C++";
puts(new);
return 0;
}

That is, one way would be to use a C++ (and not C) keyword as a variable.

[EDIT]
Another way.

Help with Code Tags

(Toggle Plain Text)

#include <stdio.h>
 
#ifdef __cplusplus
#error Prevented from compiling as C++
#endif
 
int main(void)
{
puts("Hello world");
return 0;
}

[/EDIT]

•

Join Date: Mar 2004

Posts: 77

Reputation: infamous is an unknown quantity at this point

Solved Threads: 2

infamous

Offline

Junior Poster in Training

Re: How do you write a code which compiles in c but not in c++?

May 6th, 2004

LOL good thinking

•

Join Date: Mar 2004

Posts: 1,620

Reputation: kc0arf is a jewel in the rough

Solved Threads: 51

kc0arf

Offline

Posting Virtuoso

Re: How do you write a code which compiles in c but not in c++?

May 6th, 2004

Hi,

C++ is a superset of C.

I can only wonder WHY you would want to try to compile something that works with C only? That doesn't make sense.

Christian

•

Join Date: Apr 2004

Posts: 113

Reputation: liliafan is on a distinguished road

Solved Threads: 2

liliafan

Offline

Junior Poster

Re: How do you write a code which compiles in c but not in c++?

May 7th, 2004

•

Originally Posted by kc0arf

Hi,

C++ is a superset of C.

I can only wonder WHY you would want to try to compile something that works with C only? That doesn't make sense.

Christian

I seemed to remember reading about some incompatibilities that were valid C and not C++ code after doing a few minutes googling I found this link:

http://david.tribble.com/text/cdiffs.htm

Whilst most of the incompatibilities exist only in theory between the ISO99 standard C and C++ there does exist some problems such as:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
extern int foo();
 
void main()
{
   foo(1,2);
}
extern int foo();

void main()
{
   foo(1,2);
}

Is valid C but will cause an error in C++, in 2 places with g++ since main must return an int, and there is too many arguements passed in foo, in C it is assumed that extern int foo() calls a function with an unspecified number of arguements where as C++ assumes it is called a function with no arguements ie: extern int foo(void)

So whilst there shouldn't be incompatibilities some do exist due to language evolution.

Btw most of the incompatibilities on the link included are theoretical also with some compilers the incompatibility I have shown will be detected with others it won't according to the standard it is invalid C++ but valid C, and when I tested this will gcc and g++ it showed the problem.

HTH
Ben

Application development, webhosting, and much more: www.webcentric-hosting.com

•

Join Date: May 2004

Posts: 141

Reputation: meabed is on a distinguished road

Solved Threads: 3

meabed

Offline

Junior Poster

Re: How do you write a code which compiles in c but not in c++?

May 7th, 2004

LOL .. Nice

•

Join Date: May 2004

Posts: 4

Reputation: prabhu_kar is an unknown quantity at this point

Solved Threads: 0

prabhu_kar prabhu_kar is offline

Offline

Newbie Poster

Re: How do you write a code which compiles in c but not in c++?

May 11th, 2004

•

Originally Posted by The Other Dave

>How am i supposed to write a code in c which compiles in c but not in c++
Help with Code Tags

C++ Syntax (Toggle Plain Text)
#include <stdio.h>
 
int main(void)
{
char new[] = "Compiles in C, not in C++";
puts(new);
return 0;
}
#include <stdio.h> int main(void) { char new[] = "Compiles in C, not in C++"; puts(new); return 0; }
That is, one way would be to use a C++ (and not C) keyword as a variable.

[EDIT]
Another way.
Help with Code Tags

(Toggle Plain Text)
#include <stdio.h>
 
#ifdef __cplusplus
#error Prevented from compiling as C++
#endif
 
int main(void)
{
puts("Hello world");
return 0;
}
#include <stdio.h> #ifdef __cplusplus #error Prevented from compiling as C++ #endif int main(void) { puts("Hello world"); return 0; }
[/EDIT]