Mostly Heavy IDEs comes with this features; so no need to do anything extra, just follow few steps. Rarely I used NetBeans and RAD 7.5 for the diagrams like UMLs and class Diagrams.
I guess Eclipse and MS Visual Studio also has this facility. I have not checked.

Following links may be useful for you.
http://msdn.microsoft.com/en-us/library/aa288743.aspx
http://www.codeproject.com/KB/cs/AutoDiagrammer.aspx 
 
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From: Mario Chacon <the.masch@gmail.com>
To: boost-users@lists.boost.org
Sent: Monday, 16 February, 2009 10:27:51 PM
Subject: [Boost-users] [Question] Software documentation

Hello:
It's possible that some plugin or some another soft generate class diagram from the source??
I know that with oxygen can generate a beautiful HTML, but Can I do something more?


Salud...
masch...


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