Bit Vectors

Bit vectors can save memory by using a single scalar to hold many values. I can use a long string of bits to store the values instead of using an array of scalars. Even the empty scalar takes up some memory; I have to pay for that scalar overhead with every scalar I create. Using Devel::Size, I can look at the size of a scalar:

#!/usr/bin/perl
# devel-size.pl

use Devel::Size qw(size);

my $scalar;

print "Size of scalar is " .
  size( $scalar ) . " bytes\n";