when to include <string>

[Travis]

So here's something I've always wondered. Typically if I want to use a
string I simply

using namespace std::string;

string myString;

But when do I actually need to include <string>. What does that
provide me and why, for some uses, do I not need it?

Thanks.

[red floyd]

Re: when to include &lt;string&g t;

Victor Bazarov wrote:

Travis wrote:

>So here's something I've always wondered. Typically if I want to use a
>string I simply
>>
>using namespace std::string;

Try either

using namespace std;

or

using std::string;

but not the original text. So you'd have:

#include <string>
using namespace std;

or

#include <string>
using std::string;

>string myString;
>>
>But when do I actually need to include <string>. What does that
>provide me and why, for some uses, do I not need it?

>

You need to #include <stringwhenev er you use std::string. Either
explicitly as std::string, or via a using clause.

[Andrey Tarasevich]

Re: when to include &lt;string&g t;

Travis wrote:

So here's something I've always wondered. Typically if I want to use a
string I simply
>
using namespace std::string;

This will not even compile. You probably meant

using std::string;

string myString;
>
But when do I actually need to include <string>. What does that
provide me and why, for some uses, do I not need it?
...

If you want to use 'std::string', you have to include <stringdirect ly
or indirectly. The only reason you were able to get away without
including it yourself is that you must've included some other header
file, which included <stringinternal ly. For example, in some
implementation of standard library header <iostreammigh t include
header <stringinternal ly, so when you include <iostreamyou
automatically include <stringwithou t even noticing it. But note, that
it is not guaranteed to always be that way. In other words, you code
compiled because you've been lucky so far. If you want your code to be
portable between platforms and compiler/library versions, be sure to
include <string(directl y or indirectly) into every translation unit
that uses 'std::string'.

--
Best regards,
Andrey Tarasevich

[dave_mikesell@fastmail.fm]

Re: when to include &lt;string&g t;

On Feb 8, 1:03 pm, Travis <travis.bow...@ gmail.comwrote:

So you're saying that by including <iostream>, it then includes
<string>?

For your implementation, it appears that the iostream header includes
the string header, but as others have stated, that is not guaranteed
to be the case in other implementations . In other words, you could
try to compile your code with another compiler and it might fail. May
as well be safe and include <stringin your code.

[Travis]

Re: when to include &lt;string&g t;

On Feb 8, 12:16 pm, dave_mikes...@f astmail.fm wrote:

On Feb 8, 1:03 pm, Travis <travis.bow...@ gmail.comwrote:
>

So you're saying that by including <iostream>, it then includes
<string>?

>
For your implementation, it appears that the iostream header includes
the string header, but as others have stated, that is not guaranteed
to be the case in other implementations . In other words, you could
try to compile your code with another compiler and it might fail. May
as well be safe and include <stringin your code.

Thanks