I am writing a my own specialized version of EDIT for DOS. I was wondering if anyone else has written such a program, and if so how the went about writting it. I needed to know specifically how they stored open files in memory, I use MSVC++ 1.0 and in its editor each line can only be 256 bytes long which leads me to believe that there is an array of 256 bytes for each line in the document. Before a started on it I was wondering if anyone have used this and if there are any other, more effective was of doing this. Also I wanted to know about how to make an undo.