So, what is a console app? From a not so technically correct description console applications are applications invoked from the Windows command prompt (cmd.exe). A console app is any program with access to three basic data streams: standard input, standard output, and standard error. Standard Input represents data flowing into the program, Standard Output represents data flowing out, and Standard Error represents a special kind of data flowing out (ie error messages). The command-line arguments along with the described data streams represent the runtime context of the console app.

It's easy to recognize a console application running in Windows; it's has a very familiar black box with gray text in it. This black box is how Windows makes the standard data streams available to the user. When you type data in the black box window, you are entering ‘standard input’ to the console application and when it reply’s with text, this is actually the standard output and/or standard error).