C++20 is the next big C++ standard after C++11. As C++11 did it, C++20 changes the way we program modern C++. This change is, in particular, due to the big four of C++20: ranges, coroutines, concepts, and modules. My book C++20 is both: a tutorial and a reference for the C++20 standard. It teaches you C++20 and provides you with the details of this new thrilling C++ standard. The thrilling factor is mainly due to the big four of C++20.
Concepts change the way we think and program templates. They are semantic categories for the template parameters and enable you to express your intention directly in the type system. If something goes wrong, you get a clear error message.
The new ranges library enables it to perform algorithms directly on the container, compose the algorithm with the pipe symbol, and apply them to infinite data streams.
Thanks to coroutines, asynchronous programming in C++ becomes mainstream. Coroutines are the base for cooperative tasks, event loops, infinite data streams, or pipelines.
Modules overcome the restrictions of header files. They promise a lot. For example, the separation of header and source files becomes as obsolete as the preprocessor. In the end, we have faster built time and an easier way to build packages.