• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Tim Cooke
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Liutauras Vilda
Sheriffs:
  • Rob Spoor
  • Junilu Lacar
  • paul wheaton
Saloon Keepers:
  • Stephan van Hulst
  • Tim Moores
  • Tim Holloway
  • Carey Brown
  • Scott Selikoff
Bartenders:
  • Piet Souris
  • Jj Roberts
  • fred rosenberger

quantifiers

 
Ranch Hand
Posts: 43
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi, I was going through K&B chapter-6 the following question:

Given:
import java.util.regex.*;
class Regex2 {
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 the command line:
java Regex2 "\d*" ab34ef
What is the result?
A. 234
B. 334
C. 2334
D. 0123456
E. 01234456
F. 12334567
G. Compilation fails.

The answer to this question is : E.
Till 0123445 its clear to me but after that where this digit 6 is coming from because index 6 is not there in the input string.

Thanks
 
Sheriff
Posts: 11343
Mac Safari Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
See our SCJP FAQ: Could someone explain the Regex2 class from K&B's Java 5 Study Guide?
 
Ranch Hand
Posts: 65
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
It does seem a little confusing but I read this article from sun (regex) and it
helped me understand. What helped me nail it, was by practicing with some code examples. Copy the code from the sun article and play around with some patterns and input strings. I guarantee you will get the hang of it if you do!
Best of luck

Have a look at the above link I posted and then check this out!
http://java.sun.com/docs/books/tutorial/essential/regex/quant.html
[ July 24, 2008: Message edited by: Keith Nagle ]
 
pie. tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop
https://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton
reply
    Bookmark Topic Watch Topic
  • New Topic