We all know the "print" statement, but what I find interesting is in Dynamics 365 for Finance and Operations, Enterprise Edition, it has been changed.
It works the same, but it now uses System.Diagnostics.Debug::WriteLine("Hello World") to print to the output window.
You can read more about it and other interesting debugger features here:
https://docs.microsoft.com/en-us/dynamics365/unified-operations/dev-itpro/dev-tools/new-x-debugger-features
