I am trying to convert an integer to char array and I came across this piece of code
int i = 5; std::string s; std::stringstream out; out << i; s = out.str(); But when I try to print the value of s it still prints 5. I don't know if its supposed to do that or am I doing something wrong? Besides I would prefer if I could convert the same int to char array. But I would appreciate any help in the matter. Thanks! Code taken from: Alternative to itoa() for converting integer to string C++?
Yes, it's supposed to do that. You'd (primarily) notice the difference from just printing a number out directly if you do some other string-type manipulation on the result (e.g., concatenating it with other strings, searching for characters in the string).
Just for example:
std::cout << i+i; // should print "10" std::cout << s+s; // should print "55" Besides I would prefer if I could convert the same int to char array.
char *charPtr = new char[ s.length() + 1 ] ; // s is the string in the snippet posted strcpy( charPtr, s.c_str() ) ; // ....... delete[] charPtr ; // Should do this, else memory leak. 
std::string to strlen is illegal. It should be new char[s.length() + 1]; or new char[strlen(s.c_str()) + 1];, but of course the second one is inherently less efficient.
std::auto_ptr uses delete rather than delete [], so std::auto_ptr<char> would cause undefined behavior here. On C++0x compilers std::unique_ptr<char[]> would be preferred; on older compilers, boost::scoped_array or boost::shared_array are the best options.delete [] charPtr; rather than delete charPtr; ;-]If you would like to stop worrying about issues like that you might be interested in boost/lexical_cast.hpp.
#include <boost/lexical_cast.hpp> #include <string> #include <iostream> int main() { const int i=5; const char* s = boost::lexical_cast<std::string>(i).c_str(); std::cout << s << std::endl; } 