std::string sprintf

[Frank Neuhaus]

Hey
Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any _convenient_ and buffer overflow secure equivalent for that
using std::string?
Thanks

 

[Mike Wahler]

Hey
Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any _convenient_ and buffer overflow secure equivalent for that
using std::string?

Look up 'std:stringstream'

-Mike

 

[Victor Bazarov]

Hey

Hey yourself

Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any _convenient_ and buffer overflow secure equivalent for that
using std::string?

There is a snprintf, IIRC...

Generally speaking, the only reasonable way I know is

std:stringstream os;
os << "Hello test " << someint << ' ' << somestring;
std::string buffer(os.str());

// here 'buffer' has the string

V

 

[Matthias Kaeppler]

Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any _convenient_ and buffer overflow secure equivalent for that
using std::string?

Boost.Format has printf-style formatting by overloading operator%. It
still doesn't feel very printf-ish to me though. What you do, basically,
is create a formatter object which has an internal stream buffer holding
the formatted sequence. You can then take its string value and assign it
to a std::string.

Example:

std::string s;
s = str( format(" %d %d ") % 11 % 22 );

See http://www.boost.org/libs/format/index.html for more examples.

 

[Default User]

Hey
Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any convenient and buffer overflow secure equivalent for
that using std::string? Thanks

http://www.parashift.com/c++-faq-lite/misc-technical-issues.html#faq-39.
1


Brian

 

[Marcus Kwok]

Hey
Iam occaisonally using something like
char buffer[1024];
sprinf(buffer,"Hello test %d %s",someint,somestring);

Is there any convenient and buffer overflow secure equivalent for
that using std::string? Thanks

http://www.parashift.com/c++-faq-lite/misc-technical-issues.html#faq-39.
1

Link should be all on one line:

http://www.parashift.com/c++-faq-lite/misc-technical-issues.html#faq-39.1

 

[Frank Neuhaus]

Thanks for all suggestions
ostringstream looks like the most reasonable method for my case
Gonna look into that

 

[wenmang]

I am read the example in your link, and I have a question about
efficiency of following code:

inline std::string stringify(double x)
{
std:stringstream o;
if (!(o << x))
throw BadConversion("stringify(double)");
return o.str();
}

how expensive to create std:stringstream o again and again by calling
stringify() compared to sprintf() C function call?

 

[John Harrison]

I am read the example in your link, and I have a question about
efficiency of following code:

inline std::string stringify(double x)
{
std:stringstream o;
if (!(o << x))
throw BadConversion("stringify(double)");
return o.str();
}

how expensive to create std:stringstream o again and again by calling
stringify() compared to sprintf() C function call?

sprintf is much cheaper than ostringstream *except* when you get a
buffer overflow, when it is much, much, much more expensive.

john

 

[Default User]

Marcus Kwok wrote:

Link should be all on one line:

One of the few bad quirks of XanaNews is wrapping long URLs.



Brian

 

[Default User]

sprintf is much cheaper than ostringstream except when you get a
buffer overflow, when it is much, much, much more expensive.

And the original request specifically asked:

"Is there any convenient and buffer overflow secure equivalent for that
using std::string?"

He already had an sprintf() solution.



Brian

 

[Jacques Labuschagne]

I am read the example in your link, and I have a question about
efficiency of following code:

inline std::string stringify(double x)
{
std:stringstream o;
if (!(o << x))
throw BadConversion("stringify(double)");
return o.str();
}

how expensive to create std:stringstream o again and again by calling
stringify() compared to sprintf() C function call?

On my system the actual conversion is roughly as fast as through
sprintf, but the cost of creating and destroying a stringstream for each
conversion triples the time taken.
I've always used stringstream for the general form of my "stringify"
equivalent and then specialised the numeric versions to use snprintf.

Jacques.