//******************************************************** // The following code example is taken from the book // C++20 - The Complete Guide // by Nicolai M. Josuttis (www.josuttis.com) // http://www.cppstd20.com // // The code is licensed under a // Creative Commons Attribution 4.0 International License // http://creativecommons.org/licenses/by/4.0/ //******************************************************** #include #include #include struct Value { double amount = 0; int precision = 2; std::string unit = "Dollar"; }; int main() { Value v1{100}; // OK Value v2{.amount = 100, .unit = "Euro"}; // OK Value v3{.precision = 8, .unit = "$"}; // OK Value v4{100, .unit = "Euro"}; // ERROR: all or none designated Value v5{.unit = "$", .amount = 20}; // ERROR: invalid order Value v6(.amount = 29.9, .unit = "Euro"); // ERROR: only supported for curly braces for (Value val : {v1, v2, v3}) { std::cout << std::format("{:.{}f} {}\n", val.amount, val.precision, val.unit); } }