bit - How to do bitwise operation in perl to get the count of longest sequence of 0s between two 1s -

given integer print bit bit in perl. instance given number 9, get

1 0 0 1 

how achive this. trying is, number of longest 0s between 2 1s. meaning if bitwise representation of number 1000001001, perl function return 5.

i know whats best way code in perl. totally new perl.

with leading zeroes:

my @bits = reverse unpack '(a)*', unpack 'b*', pack 'j>', $int; 

without:

my @bits = reverse unpack '(a)*', sprintf '%b', $int; 

notes:

• reverse used place least significant bit in $bits[0].
• unpack '(a)*' used split string individual bits.
• both work signed , unsigned integers.
• both work integers of size (in bytes) given perl -v:ivsize.

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if leave string, can take advantage of regex engine extract sequences of zeroes.

use list::util qw( max ); $bin = sprintf '%b', $num; $longest = ( max map length, $bin =~ /1(0+)(?=1)/g ) || 0; 

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in c, might following, in perl, might less efficient earlier solution:

my $longest = 0; if ($num) {    # cast unsigned >> inserts zeroes neg nums.    $num = ~~$num;     # skip zeros not between 1s.    $num >>= 1 while !($num & 1);     while (1) {       # skip 1s.       $num >>= 1 while $num & 1;        last if !$num;        # count 0s.       $len = 0; ++$len, $num >>= 1 while !($num & 1);        $longest = $len if $longest < $len;    } }