C++ int to string, concatenate strings [duplicate]

Answer 1

You want to use boost::lexical_cast. You also need to include any needed headers:

#include 
#include 
std::string nStr = boost::lexical_cast(n);

then it's simply:

std::string file_name = "File-" + nStr + ".txt";

because std::strng plays nicely with string literals (e.g. ".txt").