How to programmatically create a site column and a content type

Question

Hello,
I'd like to create a site column (let's say a field text) and a content type, only  using c#  -i.e. I don't want to add new item/column and then xml. This code will be added to a FeatureActivated.My code is :
public override void FeatureActivated(SPFeatureReceiverProperties properties) {SPWeb rootweb = (SPWeb) properties.Feature.Parent;
SPFieldText field = new SPFieldText(SPfiledscollection???, "field1");
if (field != null)
rootweb.Fields.Add(field)
rootweb.Update();
}   SPContentType newContentType = new SPContentType(spcntenttypeId??, SPContentTypeCollection ??, "content1");
   rootweb.ContentTypes.Add(newContentType);
   rootweb.Update();
Are there any sample codes out there? I've only found samples using xml - which has an irritating "feature"
Thank you
Christos

Answer 1

Nice code and it helped me understand. Some small questions. I'm trying to make all the "data" for a (sub)web site.
So, I think, my steps are:
1. create site columns+content type
2. create  list
3. create a lookup site column that uses the list on <2>
4. create content type that uses the site column on <3>
5. Create the list for the content type on <4>
My confusion is: should I use one feature for everything? Your code is using scope=site, so i need to "hardcode" the web site's name. I don't mind doing that , I just don't know how to use scopes in features for creating data.
Thank you
Christos