I am assuming that you are familiar with the 9x9 Sudoku Puzzle
The objective of the Sudoku Trainer is that it "mechanizes" (but does NOT "automate") the solving process. The following explains the difference between these two approaches:
Automate = implies that the computer applies an algorithm that leads to a solution
Mechanize = implies that the computer prompts several levels of logic steps, such that a knowledgable person would apply in case of a manual solution
The following website is the basis for the mechanization of the Sudoku Trainer: http://angusj.com/sudoku/ (I recommend that you access this website)
That website shows an executable version (*.exe), but does not provide the source file
I have started the Sudoku Trainer using Visual Basic (VB), version 5.0. VB has an excellent GUI (Graphic User Interface) capability, but for complicated logic solutions it is not the best approach.
For the first few logic steps (see the website reference) I have the source code, but as the logic steps get more-and-more complicated I ran into problems