Question

I have a question about comments in C language.
When we write for example

//this is the first step

This means a comment.

But when we write

//this is the first step;

Does this also mean a comment? I mean when we add semicolon after double slash, does this mean a comment or main part of the program?

Answer 1

The double slash comments out the line yes. The compiler will ignore the whole line (including semi-colons, yes).

For multi line comments, or commenting on the same line as some code, use /* comment here */

Wiki has some good information here: http://en.wikipedia.org/wiki/C_syntax#Comments

Note (from Wiki):

C++ style line comments start with // and extend to the end of the
line. This style of comment originated in BCPL and became valid C
syntax in C99; it is not available in the original K&R C nor in ANSI
C: