Welcome to collectivesolver - Programming & Software Q&A. A website you can trust. All programs tested and works. Contact: aviboots(AT)netvision.net.il
Bonsai Boy of New York Bonsai Trees and Accessories

BlueHost Web Hosting

Liquid Web Managed Dedicated Server: RAID 1 SSD with 16GB of RAM minimum! 24/7 On-Site Heroic Support! Industry-Leading SLA!

Ecommerce Software - Best Ecommerce Platform Made for You - Free Trial

Ecommerce Software - Best Ecommerce Platform Made for You - Free Trial

getflywheel wordpress hosting


Liquid Web Cloud VPS Hosting

10,405 questions

14,169 answers

573 users

How to get the highest power of 2 that is less than or equal to N in PHP

1 Answer

0 votes
function highest_power_of_2_less_or_equal_to_n($n) { 
    $power = 0; 
    for ($i = $n; $i >= 1; $i--) { 
        // $i == power of 2 ?
        if (($i & ($i - 1)) == 0) { // 10 (1010) 9 (1001) 8 (1000) 7 (0111)
            $power = $i; 
            break; 
        } 
    } 
    return $power; 
} 

$n = 17;
echo highest_power_of_2_less_or_equal_to_n($n) . "<br >"; 
      
$n = 10;
echo highest_power_of_2_less_or_equal_to_n($n) . "<br >"; 
      
$n = 64;
echo highest_power_of_2_less_or_equal_to_n($n) . "<br >"; 
 
 
 
/*
run:
      
16
8
64
     
*/

 




answered Apr 13 by avibootz
...