When you compile a C# project, the app settings from app.config are saved along with the exe file. For example, if the program name is \"solve_np.exe\", there will be a \"so
Typically the theory of a configuration file, is that it stores settings you may want to change once you've deployed the application (for something like user preferences). To do this, you need to be storing somewhere external to your application. If you use the default setup, you get "[Your].exe.config". There are many other options you could look at, but nearly every one of them ends up with a file written somewhere, if you providing a mechanism that saves settings of some kind.