to #include or not to #include

When using functions that are in the standard library, I find that to use them I sometimes have to include the appropriote header, and sometimes I do not. e.g the strlen() function: I can use it without including the header it needs....

can anyone tell me why?

p.s. Just thought it would be fun to tell ya´ll, I´m in Mexico at an internet cafe, the cost is 10 pesos (aprx. $1 USD) per hour...not bad... and since I´m not near a compiler, I´m not sure for certain whether the strlen() will work without a header. sorry if it doesn´t.

(using vc++ .net at home)

if you include a header, that header might in turn, include a header, which might include a header, etc, etc....<iostream> seems to include the necessary header for strlen


i always include everything that i need whether or not i really need too...this will help ensure that a change in one header doesn't break your program (as far as includes go)

who are you asking?

edit: hmmmm..the previous post disappeared

sorry, for that, I didn't quite understand the previous post... that's why my reply was confusing.

It doesn't hurt to include something that another header file has already included, so just save yourself the trouble (not to mention everybody who reads your code) and include everything.

edit: everything that you USE, that is...

everything that you USE, that is...

har har.

>so just save yourself the trouble (not to mention everybody who reads your code) and include everything.

Code:

#ifndef EVERYTHING
#define EVERYTHING

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <cwchar>
#include <cwctype>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <strstream>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

#endif

Code:

#include "everything.h"

int main()
{
  //...
}

>edit: everything that you USE, that is...
Feh, party pooper.

I've been working with C too long... That file looks way too big and I don't even recognize half the files in there!

I think I'll use that header file in all of my examples from now on. I'll also be sure to use the most obscure solution I can imagine. That way you guys won't know what the hell I'm talking about most of the time.

Like we do now?