Regex test in scjp test

Question

I am trying to solve an scjp test about regex.

here is a code...

import java.util.regex.*;

public class TestRegex {
    public static void main(String[] args) {
        Pattern p = Pattern.compile(args[0]);
        Matcher m = p.matcher(args[1]);
        boolean b = false;
        while (b = m.find()) {
            System.out.print(m.start() + m.group());
        }
    }
}

and

java TestRegex "\d*" ab34ef

the answer for this test is 01234456. I understood everything except the last output(6). Since the last index in "ab34ef" is 5, how is it possible to be printed 6 ?

Any help ....

...would be greatly appreciated? – sp00m Mar 25 '13 at 16:18 — sp00m, Mar 25 '13 at 16:18

score 5 · Answer 1 · answered Mar 25 '13 at 16:18

5

\d* means "zero or more digits," which can actually match nothing. The 6 is a match against the empty string after the last character in the string.

answered Mar 25 '13 at 16:18

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ok..thanks..is this empty string regex specific, or it is inherent to all strings? – tural Mar 25 '13 at 16:30
@tural I don't really know what you mean .. it has to do with the regex – Explosion Pills Mar 25 '13 at 18:10

Regex test in scjp test

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