commentting problem when coding in c

[Ronald]

For example:

for () {                       //comment a
        int i=0;               //comment b
}

but in emacs, I can't use tab to indent the comment, and the code will like:
for () {//comment a
        int i=0;//comment b
}

Howerver, C-q [tab] works, but it is not convenient. So does spaces.

Is there any more convenient way?