i have stumbled upon an amazing thing... if (n < 0 || n > DimX * DimY-1) return; That line of code makes my program un-operable.. ie it stops responding before it even starts.. But the catch is the code isnt executed yet because i have in line watchers which stops me in the alogrithiam and then i do it step by step so the code is never executed but if i comment it out... The crash is fixed..! funny

When you run it, are you using release or debug mode? Break points usually get ignored in release mode, so it might be getting executed after all.

Also, what does the code around that line look like? Sometimes a typo in one part of the code can screw up something later.

Checking the memory integrity is always a good way to catch errors. ( The CRT Debug routines can do this. )