Using std::format with user-defined types

The C++20 formatting library is a modern alternative to using printf-like functions or the I/O streams library, which it actually complements. Although the standard provides default formatting for basic types, such as integral and floating-point types, bool, character types, strings, and chrono types, the user can create custom specialization for user-defined types. In this recipe, we will learn how to do that.

Getting ready

You should read the previous recipe, Formatting text with std::format, to familiarize yourself with the formatting library.In the examples that we'll be showing here, we will use the following class:

struct employee
{
   int         id;
   std::string firstName;
   std::string lastName;
};

In the next section, we'll introduce the necessary steps to implement to enable text formatting using std::format() for user-defined types.

How to do it...

To enable formatting using the new formatting library for user-defined...