[Solved] Behaviour of Java RegExp ‘?’ and ‘+’ [duplicate]

Question

The regular expression [abc]? matches zero or one character that can be either a, b, or c. Thus it does not match abc. Positive matches would be the empty string, a, b, or c.

On the other hand [abc]+ matches one or more characters that can be either a, b, or c. Therefore, it can match the 3 character string abc. Also aaa or bbba would match.

Accepted Answer

The regular expression [abc]? matches zero or one character that can be either a, b, or c. Thus it does not match abc. Positive matches would be the empty string, a, b, or c.

On the other hand [abc]+ matches one or more characters that can be either a, b, or c. Therefore, it can match the 3 character string abc. Also aaa or bbba would match.