Adding content type programatically

Scenario:
You want to add Content Type programatically

Solution:
SharePoint Object Model

Code:

1. using (SPSite site = new SPSite("http://localhost")) {   
2.   
3. using (SPWeb web = site.OpenWeb()) {   
4.   
5. SPContentType baseType = web.AvailableContentTypes["Document"];  
6.   
7.  SPContentType proposal = new SPContentType( baseType, web.ContentTypes, "Project Proposal");   
8.   
9. proposal.FieldLinks.Add(new SPFieldLink(web.AvailableFields["Author"]));   
10.   
11. web.ContentTypes.Add(proposal);   
12.   
13. }  
14. }