what is difference between web.config and app.config files in .Net Applications

Web.Config:

Web.Config files are purely for web applications.

This file is automatically created when we create new web projects.

we can have many web.config files in web project where each folder can contain single web.config file only.

In this files we can able to store global information which can be accessed based on location of the 

config file. Whenever we change these file automatically website will restart with modified details.

App.Config:

App.Config files are for Windows Application.

This file is not add by default when we create new project. We need to externally add these to file to our project by Right Clicking on project --> Select Add New Item--> Select "Application Configuration file".

Modifying App.Config file will not affect the running application until we restart the application.Only one app.config file is allowed in one project.