std::string, Append a number

[JKop]

The following isn't doing what I thought it would do:

#include <iostream>

int main()
{
int k = 56;

std::string blah(" ");

blah += k;

std::cout << "\n\n" << blah << "\n\n";
}



How do I simply append a number to an std::string?


As in:

"Amount: "

becoming

Amount: 56"

?

Thanks,

-JKop

 

[Sumit Rajan]

The following isn't doing what I thought it would do:

#include <iostream>

int main()
{
int k = 56;

std::string blah(" ");

blah += k;

std::cout << "\n\n" << blah << "\n\n";
}



How do I simply append a number to an std::string?


As in:

"Amount: "

becoming

Amount: 56"

You could try something like this:

#include <string>
#include <iostream>
#include <sstream>

int main()
{
std::string s("Amount:");
int tot = 42;
std:stringstream oss;
oss << s << ' ' << tot << '\n';
std::cout << oss.str();
}

Regards,
Sumit.

 

[Andre Kostur]

You could try something like this:

#include <string>
#include <iostream>
#include <sstream>

int main()
{
std::string s("Amount:");
int tot = 42;
std:stringstream oss;
oss << s << ' ' << tot << '\n';
std::cout << oss.str();
}

... or look up the lexical_cast<> item in Boost (http://www.boost.org)...
(which I think does the same thing )

 

[Zian Smith]

The following isn't doing what I thought it would do:

#include <iostream>

int main()
{
int k = 56;

std::string blah(" ");

blah += k;

std::cout << "\n\n" << blah << "\n\n";
}



How do I simply append a number to an std::string?


As in:

"Amount: "

becoming

Amount: 56"

?

Thanks,

-JKop

Use ostringstream to convert the int to a string type:


main()
{
int k=56;
std::string blah("woot ");

std:stringstream os;
os << k;
std::string k_str = os.str(); //retrieve as a string

blah += k_str;
std::cout << blah << "\n\n";
}

 

[Matt Hurd]

.. or look up the lexical_cast<> item in Boost (http://www.boost.org)...
(which I think does the same thing )

Yes, boost::lexical_cast is nicer, it hides the stream usage.

Specific reference here: http://www.boost.org/libs/conversion/lexical_cast.htm

This is the code, FYI, using your example.

#include <iostream>
#include <boost/lexical_cast.hpp>

int main()
{
int k = 56;

std::string blah(" ");

blah += boost::lexical_cast<std::string>(k);

std::cout << "\n\n" << blah << "\n\n";
}

Regards,

Matt Hurd
www.hurd.com.au