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From: | CBFalconer <cbfalconer AT yahoo DOT com> |
Organization: | Ched Research http://cbfalconer.home.att.net |
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Newsgroups: | comp.os.msdos.djgpp |
Subject: | Re: to check given no. is power of 2 |
References: | <1116997063 DOT 905915 DOT 71670 AT z14g2000cwz DOT googlegroups DOT com> |
Lines: | 23 |
Date: | Wed, 25 May 2005 13:15:51 GMT |
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To: | djgpp AT delorie DOT com |
DJ-Gateway: | from newsgroup comp.os.msdos.djgpp |
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aveo wrote: > > i need a C code that checks given no. is power of 2 or not without > checking any condition. int qpwrof2(unsigned long n) { return (n && (!(n & (n-1)))); } /* untested */ assuming n == 0 is not considered a power of 2. Function names beginning with 'is' are reserved, so I use q for query. The above should handle values up to 32 bits and return 0 or 1 only. -- Some useful references about C: <http://www.ungerhu.com/jxh/clc.welcome.txt> <http://www.eskimo.com/~scs/C-faq/top.html> <http://benpfaff.org/writings/clc/off-topic.html> <http://anubis.dkuug.dk/jtc1/sc22/wg14/www/docs/n869/> (C99) <http://www.dinkumware.com/refxc.html> (C-library} <http://gcc.gnu.org/onlinedocs/> (GNU docs)
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