A Read-Eval-Print-Loop (REPL) is an interactive program that reads your input, evaluates it, prints the result, and loops back to the beginning. It’s a great way to experiment with a programming language and an excellent method for learning a new language. C# has many REPLs; some are web-based, others are desktop applications, and some are command-line tools. There’s .NET Fiddle, Try .NET, the popular LINQPad, the built-in csi.exe, and many more.
