I followed Lardmeister's smart hints about creating templates with VC# 2003 and using SnippetCompiler.exe to write and test the rest of the program. It also allows you to build the executable (only 7k in size). The algorithm is from one of my Python snippets I wrote a long time ago. It only took occasional mild headscratching to convert it to C# code. The nice thing is that you end up with only 2 small files 'Mortgage.cs' and 'Mortgage.exe'. Doing the same with VC# 2005 creates over a dozen files and splits your source code up, reminds me of Delphi. I guess the apple does not fall far from the horse!