std::cout << ("Hello, world," + QuantLib::DoubleFormatter::toString(dummy) + " is a number") << std::endl;
void HelloWorld() {    double dummy = 5.7;    std::cout << "Hello, world" << std::endl;    std::cout << ("Hello, world," + QuantLib::DoubleFormatter::toString(dummy) + " is a number")        << std::endl;}