Well, they're green aren't they? At least they are for me.
C comments come in blocks between
*/ and can span any number of lines. C++,
C99, C#, and Java add the single line comment that follows
//. Other languages provide similar
block and line comment facilities,
but with different syntaxes.
Again, this is elementary subject matter. But the different comment markers are often used in subtly different ways. We'll see examples as we go along. However, any commenting scheme that makes cute use of subtle syntax differentiations should be viewed warily.