Re: Is it odd or even??? Optimize!!!

Clever. For those of us unfamiliar with bitwise ops, here's how this works: The bitwise and op (&) works on bits like this: dig1 dig2 Result 0 0 0 0 1 0 1 0 0 1 1 1 An even number's binary representation always ends with 0 (ie 12 = 1100) while an odd ends with 1 (ie 13 = 1101). So doing a bitwise & with 1 will only produce 1 if the last binary digit is 1 (ie an odd num), otherwise 0 (see table). And, like Nathan implies, this will be very fast (way faster than modulus), since you only ever deal with 2 bits of info. For an explanation of other bitwise operators, look here: http://java.sun.com/docs/books/tutorial/java/nutsandbolts/bitwise.html J on 3/5/01 12:36 PM, Nathan Cassano at nathan@cjhunter.com wrote: > > You all are a bunch of un-optimizing novices. Just do some bit banging. > > i.e. > > if(1 & number){ > echo "$number is odd"; > }else{ > echo "$number is even"; > } > > > -----Original Message----- > From: Brandon Orther [mailto:brandon@webintellects.com] > Sent: Monday, March 05, 2001 12:18 PM > To: PHP User Group > Subject: [PHP] Is it odd or even??? > > > Hello, > > Is there an easy way to check and see if a number is odd or even? > > Thank you, > > -------------------------------------------- > Brandon Orther > WebIntellects Design/Development Manager > brandon@webintellects.com > 800-994-6364 > www.webintellects.com > -------------------------------------------- >