c++ equivalent of this code below (sprintf)

Question

What is the C++ equivalent of the code below?

sprintf(name,"jari%d.jpg",rank+42+size);

help me how to change it to c++. can anyone help me?

Answer 1

I would suggest an ostringstream:

string name;
{
    ostringstream oss;
    oss << "jari" << (rank+42+size) << ".jpg";
    name = oss.str();
}

Details: To use this solution, you'll want #include <sstream> and pull ostringstream into scope with using std::ostringstream; (or just use std::ostringstream directly qualified).

Answer 2

The equivalent would be:

#include <sstream>

std::ostringstream s;
s << "jari" << rank + 42 + size << ".jpg";
std::string name = s.str();

Not exactly equivalent in terms of data types, since the final result is a std::string instead of a char*, but the most idiomatic.

Outputting the formated string directly is even simpler:

std::cout << "jari" << rank + 42 + size << ".jpg";

Alternatively, there is also the Boost Format library that offers similar functionality:

#include <boost/format.hpp>

boost::format formatter("jari%1%.jpg");
formatter % rank+42+size;
std::string name = formatter.str();

or to directly output the string:

std::cout << boost::format("jari%1%.jpg") % rank+42+size;

Answer 3

or you can use boost format library

cout << boost::format("jari%1%.jpg") % (rank + 42 + size)