Regex Nested Quantifier *

Question

I am trying to use Regex to make a comment finder in text, but I get the error 'Nested Quantifier *'

Regex Comment = new Regex("/*.*?*/");

As in: It starts at /* and ends at */ [Comments]

What is the problem with doing this?

Answer 1

Its because literal * must be escaped \\* . Otherwise the regex engine take it for the quantifier * (zero or more time). The error message you obtain is relative to *?* (the regex engine see two consecutive quantifiers *? and * )

You can write your pattern like this:

Regex Comment = new Regex(@"(?s)/\*.*?\*/");

(I added the (?s) modifier to allow the dot to match newlines)