It really doesn''t matter, just as long as you are consistent throughout all your code. So if you want to go with the lower one (which does look pretty ok) you need to do it throughout all source files, otherwise confusion might arise.
Then later, if you get employed at a company that has their own convention of writing comments then you''ll have to stick to it.
If you ask me, I''d do it like this if I had to know the various variables:
// set a 2D parallel projection viewglOrtho( 0.0,w,h,0.0,0.0,100.0 ); // left, right, bottom, top, non-important, zNear, zFar
