lst-0033-book.cpp
// https://godbolt.org/z/TT13E3sz5
#include <sstream> // ostringstream
#include <iostream>
int main() {
std::ostringstream ostr;
double dval = 3.1415;
int ival = 4321;
ostr << dval << " : " << ival;
const std::string sval = ostr.str();
std::cout << sval << std::endl; // Output: 3.1415 : 4321
}