Using regex to find multiple matches between two strings

Imagine I have a string like this:

c x c x A c x c x c B c x c x

And I want to find any "c" character that is between "A" and "B". So in this example I need to get 3 matches.

I know that I can use lookahead and lookbehind tokens. So I used this regex:

(?<=A).*c.*(?=B)

But it gets all the sting between A and B: c x c x c as one result.

And if I remove the .* parts, there will be no match at all.

I made an example here. so you can see the results.

Solution

There are two common scenarios here: 1) the A and B are different single character strings, 2) A and B are different mutlicharacter strings.

Scenario 1

You may use negated character classes:

(?:\G(?!^)|A)[^AB]*?\Kc(?=[^AB]*B)

See this regex demo. Details:

(?:\G(?!^)|A) - A or end of the previous successful match
[^AB]*? - any zero or more chars other than A and B, as few as possible
\K - match reset operator that discards all text matched so far in the overall memory match buffer
c - a c char/string
(?=[^AB]*B) - that must be followed with zero or more chars other than A and B and then B char immediately to the right of the current location.

Scenario 2

If A and B are placeholders for multichar strings, say, ABC and BCE and the c is some pattern like c\d+ (to match c and one or more digits after it) use

(?s)(?:\G(?!^)|ABC)(?:(?!ABC).)*?\Kc\d+(?=.*?BCE)

See this regex demo. Details:

(?s) - a DOTALL modifier that makes the regex engine match any char with .
(?:\G(?!^)|ABC) - ABC or end of the previous successful match
(?:(?!ABC).)*? - any char, 0 or more times, that does not start an ABC char sequence
\K - match reset operator
c\d+ - c and one or more digits
(?=.*?BCE) - any zero or more chars, as few as possible, followed with BCE.