How to format string in boost library

Question

I want to format string with boost library in C++. I am doing as below.

std::string msg = "Version: %1. Version %2.";
boost::format formatter(msg.c_str());
formatter % "v1" % "v2";
xyz_function(msg);

We can do that with sprintf in one statement so is there a way to optimize above boost implementation for string formation in one statement or something other ?

Thanks in Advance.

Answer 1

A boost::format object can be cast to a string and it also has an explicit conversion function.

boost::format fmt
    = boost::format("Luke %1% and Han %2%.") % "Skywalker" % "Solo";

So either of these can be used:

• std::string fmtStr = boost::str(fmt);
• std::string fmtStr = fmt.str();

See example and demonstration, and Boost Library Format; getting std::string for the boost::str tip.