asp.net mvc - Unsure about parameter -

i working on beginner's mvc tutorial. wondering if explain how or parameters of method chosen?

public actionresult details(int id) {     var album = storedb.albums.find(id);     return view(album); }

there 2 ways id parameter populated:

 http://www.example.com/{controller}/details/{id}

 http://www.example.com/{controller}/details?id={id}

where {controller} name of controller, eg. name of homecontroller.cs "home" , {id} int.

EXC