Programmatically rename a file inside a SharePoint document library

Even if sharepoint file name property is read only you can rename a file by checking it out. more details

Rename a File in a SharePoint document library through object model

we have to first check-out the file and after renaming the file we have to check-in it more

How we can create documents inside a document library based upon the content type’s document template?

SPFile oFile = projectDocumentLibrary.RootFolder.Files.Add("TestDoc1.doc", oWeb.GetFile(oContentType .DocumentTemplateUrl).OpenBinary(), true);

more