#!/usr/bin/env perl
use warnings;
use strict;
use ntheory ":all";

cesaro("drand48", sub { int(rand(1<<32)) } );
cesaro("ChaCha20", sub { irand64 } );
cesaro("/dev/urandom", sub { unpack("Q",random_bytes(8)) } );

sub cesaro {
  my($name, $rng) = @_;

  print "Using $name:\n";
  for my $e (1..7) {
    my $n = 10**$e;
    my $t = 0;
    for (1..$n) { $t++ if gcd( $rng->(), $rng->() ) == 1; }
    printf "%8d  %10.8f\n", $n, sqrt(6*$n/$t);
  }
  print "       Pi ", Pi(), "\n\n";
}