I am new to SharePoint 2013. I want to develop the app and web parts using visual studio 2012 express edition. Can I use vs 2012 express edition to create app and web parts for SharePoint 2013? Can any one help me.
Well you can do it ,but you will need to write all your code, and create the structure for the webparts yourself.
If you use Professional or Ultimate you will have access to the SharePoint templates that will greatly improve your developing experience when for example creating apps.
If you want to use Express you would need to reference the SharePoint.dll(s) and also mimic the structure of the templates that is delivered with Office Developer Tools for the more expensive Visual Studio versions.
This blogpost is quite old and for 2007, but it shows you some more information regarding what you would have to do to make the simplest webpart without using Office Developer Tools.
This link may will help you:
By the way: