I hope comp.lang.c will not find the following question as a
complete off-topic.
I would like to remove ie.comment out the 'cout' statements during
compilation(act ually preprocessing) time.
The statements like this:
cout<<"somethin g\n" ;
should be made as
// cout<<"somethin g\n" ;
I tried for the following. But, It doesn't seem to be working.
//--------START
#ifdef DEBUG
#define COUT std::cout
#else
#define COUT \/\/
#endif
int main()
{
COUT<<"HELLO\n" <<std::endl ;
}
//--------END
If you can solve the above problem, please suggest a way for taking
care of
commenting out the 'cout' statements that spans in more than 1 line.
eg:
12 COUT<<"HELLO\n"
13 <<"WORLD\n" ; 18 6792
"qazmlp" <qa********@red iffmail.com> wrote in message
news:db******** *************** ***@posting.goo gle.com... I hope comp.lang.c will not find the following question as a complete off-topic.
I would like to remove ie.comment out the 'cout' statements during compilation(act ually preprocessing) time.
The statements like this: cout<<"somethin g\n" ; should be made as // cout<<"somethin g\n" ;
I tried for the following. But, It doesn't seem to be working.
//--------START #ifdef DEBUG #define COUT std::cout #else #define COUT \/\/ #endif
int main() { COUT<<"HELLO\n" <<std::endl ; }
//--------END
If you can solve the above problem, please suggest a way for taking care of commenting out the 'cout' statements that spans in more than 1 line. eg:
12 COUT<<"HELLO\n" 13 <<"WORLD\n" ;
This is most definately a c++ question, but the same concept works in c.
The preprocessor directly copies across what you have in a define, so why
not just have
#define COUT //
Allan
"qazmlp" <qa********@red iffmail.com> wrote in message
news:db******** *************** ***@posting.goo gle.com... I hope comp.lang.c will not find the following question as a complete off-topic.
I would like to remove ie.comment out the 'cout' statements during compilation(act ually preprocessing) time.
The statements like this: cout<<"somethin g\n" ; should be made as // cout<<"somethin g\n" ;
Sorry, it is off-topic here. cout is a part of C++, not C.
[snip]
--
Jeff
"Jeff" <no****@notexis t.com> wrote... "qazmlp" <qa********@red iffmail.com> wrote in message news:db******** *************** ***@posting.goo gle.com... I hope comp.lang.c will not find the following question as a complete off-topic.
I would like to remove ie.comment out the 'cout' statements during compilation(act ually preprocessing) time.
The statements like this: cout<<"somethin g\n" ; should be made as // cout<<"somethin g\n" ;
Sorry, it is off-topic here. cout is a part of C++, not C.
Sorry, Jeff, statements explaining what is off-topic in
comp.lang.c are off-topic in comp.lang.c++. And give "qazmlp"
a break, he expressed his hope, didn't he?
Victor
"Allan Bruce" <al*****@TAKEAW AYf2s.com> wrote... [...] This is most definately a c++ question, but the same concept works in c.
Why is it "definately " a C++ question? C has end-of-line comments.
Depending on how 'cout' is declared, it can be seen as a valid C
construct as well (just as in C++ I can declare it whatever I want
without including the <iostream>).. .
The preprocessor directly copies across what you have in a define, so why not just have #define COUT //
Why not? Simple. Comments are replaced with a single space char
before macro processing is ever begins. So, the directive you
wrote will be
#define COUT
after the phase 3 of the translation in both languages.
Victor
"Derk Gwen" <de******@HotPO P.com> wrote... # //--------START # #ifdef DEBUG # #define COUT std::cout # #else # #define COUT \/\/ # #endif
How about #ifdef DEBUG #define COUT if (1) std::cout #else #define COUT if (0) std::cout #endif
If you optimise, the unexecutable code after if (0) should be excised.
# 12 COUT<<"HELLO\n" # 13 <<"WORLD\n" ;
if (1) std::cout <<"HELLO\n" <<"WORLD\n" ;
if (0) std::cout <<"HELLO\n" <<"WORLD\n" ;
This approach has a major flaw. Imagine what this will expand into
if (somecondition)
COUT << "HELLO";
else
puts("condition is not met");
This is why it's better to use 'while' for that:
#ifdef WHATEVER
#define COUT std::cout
#else
#define COUT while(0) std::cout
#endif
However, that doesn't address the OP's concern that the code still
remains not compileable by a C compiler. It would be much better
to remove any reference to 'std::cout' whatsoever.
#ifdef __cplusplus
#define COUT std::cout
#else
#define COUT ????
#endif
I don't have a solution. The biggest problem in such case is how
you deal with user-define types that can be output using the C++
shift operator:
SomeUDT udt;
std::cout << udt; // is not uncommon in C++ programs
Making the whole statement invisible to the compiler (after the
preprocessing stage) is the task at hand (or at least how I see
it)...
Victor
On Fri, 8 Aug 2003 11:24:26 -0400, "Victor Bazarov"
<v.********@att Abi.com> wrote: "Allan Bruce" <al*****@TAKEAW AYf2s.com> wrote... [...] This is most definately a c++ question, but the same concept works in c.
Why is it "definately " a C++ question? C has end-of-line comments. Depending on how 'cout' is declared, it can be seen as a valid C construct as well (just as in C++ I can declare it whatever I want without including the <iostream>).. .
I'm curious - just how would you declare 'cout" to make
std::cout<<"HEL LO\n"<<std::end l ;
a valid C construct?
--
Al Balmer
Balmer Consulting re************* ***********@att .net
"Alan Balmer" <al******@att.n et> wrote... On Fri, 8 Aug 2003 11:24:26 -0400, "Victor Bazarov" <v.********@att Abi.com> wrote:
"Allan Bruce" <al*****@TAKEAW AYf2s.com> wrote... [...] This is most definately a c++ question, but the same concept works in
c. Why is it "definately " a C++ question? C has end-of-line comments. Depending on how 'cout' is declared, it can be seen as a valid C construct as well (just as in C++ I can declare it whatever I want without including the <iostream>).. .
I'm curious - just how would you declare 'cout" to make
std::cout<<"HEL LO\n"<<std::end l ;
a valid C construct?
I didn't say that the entire statement is a valid construct.
I said 'cout' could be a valid construct. To make 'cout' valid
all you need to do is
int cout;
In the context of the thread there was no requirement to make
'std::cout<<"HE LLO\n"<<std::en dl ;' a valid C construct.
Victor
"Alan Balmer" <al******@att.n et> wrote... On Fri, 8 Aug 2003 13:40:58 -0400, "Victor Bazarov" <v.********@att Abi.com> wrote:
"Alan Balmer" <al******@att.n et> wrote... On Fri, 8 Aug 2003 11:24:26 -0400, "Victor Bazarov" <v.********@att Abi.com> wrote:
>"Allan Bruce" <al*****@TAKEAW AYf2s.com> wrote... >> [...] >> This is most definately a c++ question, but the same concept works
inc. > >Why is it "definately " a C++ question? C has end-of-line comments. >Depending on how 'cout' is declared, it can be seen as a valid C >construct as well (just as in C++ I can declare it whatever I want >without including the <iostream>).. .
I'm curious - just how would you declare 'cout" to make
std::cout<<"HEL LO\n"<<std::end l ;
a valid C construct?
I didn't say that the entire statement is a valid construct. I said 'cout' could be a valid construct. To make 'cout' valid all you need to do is
int cout;
In the context of the thread there was no requirement to make 'std::cout<<"H ELLO\n"<<std::e ndl ;' a valid C construct.
Victor The context of the thread was that you were contesting the statement that the OP's question concerned C++.
No, I wasn't. That's something you just invented. The OP's question
concerns both C++ and C. Off-topicality of the OP's question in
comp.lang.c is what I was contesting.
Victor
"qazmlp" <qa********@red iffmail.com> wrote in message
news:db******** *************** ***@posting.goo gle.com... I hope comp.lang.c will not find the following question as a complete off-topic.
I would like to remove ie.comment out the 'cout' statements during compilation(act ually preprocessing) time.
The statements like this: cout<<"somethin g\n" ; should be made as // cout<<"somethin g\n" ;
I tried for the following. But, It doesn't seem to be working.
//--------START #ifdef DEBUG #define COUT std::cout #else #define COUT \/\/ #endif
int main() { COUT<<"HELLO\n" <<std::endl ; }
//--------END
If you can solve the above problem, please suggest a way for taking care of commenting out the 'cout' statements that spans in more than 1 line. eg:
12 COUT<<"HELLO\n" 13 <<"WORLD\n" ;
Maybe you could create your own stream and use that as cout, i.e
#if !defined(DEBUG) && defined(__cplus plus)
class MyStream : public std::ostream \
{ \
template <class T> \
MyStream& operator << (const T& obj) \
{ return *this; } \
}; \
#define COUT MyStream
#else
#define COUT std::cout
#endif
I'm not sure if the above code will work, I'm especially not too sure about
the template bit. And it most definitely would not work on c systems! Maybe
you could define cout to be an int and the << operator to be + , i.e
#if !defined(DEBUG) && !defined(__cplu splus)
int bogus_cout;
#define COUT bogus_cout=
#define << +
#elif !defined(DEBUG) && defined(__cplus plus)
class MyStream : public std::ostream \
{ \
template <class T> \
MyStream& operator << (const T& obj) \
{ return *this; } \
}; \
#define COUT MyStream
#else
#define COUT std::cout
#endif
But you would need to be 100% sure that the code in question does not use
the << _anywhere_. Hope this helps anyway!
S. Armondi This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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last post by:
I hope comp.lang.c will not find the following question as a
complete off-topic.
I would like to remove ie.comment out the 'cout' statements during
compilation(actually preprocessing) time.
The statements like this:
cout<<"something\n" ;
should be made as
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