Seonglae Chowhich is preprogrammed for all standard C++ data types
sends bytes to an output stream object
Using Insertion Operators and Controlling Format
This topic shows how to control format and how to create insertion operators for your own classes. The insertion (<< ) operator, which is preprogrammed for all standard C++ data types, sends bytes to an output stream object. Insertion operators work with predefined "manipulators," which are elements that change the default format of integer arguments.
https://learn.microsoft.com/en-us/cpp/standard-library/using-insertion-operators-and-controlling-format?view=msvc-170
