Diff - A File Compare Utility
Diff shows the differences between two text files. Call the program as
Diff [ filename1 [ filename2 ]]
or open the files from within the application using the Open buttons. The program shows the two files in text boxes above each other. Select the characters from where the comparison should start in both texts and click Compare. This will set the selection to the first character in which the two files differ. If you want to ignore white space in the comparison check the box "Skip white space".
You can download the executable and the sources in C#.
Author: Hanspeter Mössenböck