You can strip out all strings that aren't in comments by searching for the regular expression:
'[^'\r\n]+'|(//.*|/\*(?s:.*?)\*/)
and replacing with:
$1
Essentially, this searches for the regex string|(comment)
which matches a string or a comment, capturing the comment. The replacement is either nothing if a string was matched or the comment if a comment was matched.
Though regular expressions are not a replacement for a real parser you can quickly build a rudimentary parser by creating a giant regex that alternates all of the tokens you're interested in (comments and strings in this case). If you're writing a bit of code to handle comments, but not those in strings, iterate over all the matches of the above regex, and count the characters in the first capturing group if it participated in the match.