use strict;
use Algorithm::Loops qw( NestedLoops );
my $bits= 8;
my $ones= 5;
my $iter= NestedLoops(
    [   [ 0 .. $bits - $ones ],
        map(
            {   # Need lexical for closure
                my $top= $bits - $ones + $_;
                sub {
                    [ 1+$_[-1] .. $top ]
                }
            }
            1 .. $ones-1,
        ),
    ],
);
my @ones;
while(  @ones= $iter->()  ) {
    my @bits= (0) x $bits;
    @bits[@ones]= (1) x $ones;
    print join '', @bits, $/;
}