use strict;

# Definition from HOP page 122
sub NEXTVAL { $_[0]->() }

# HOP top of page 123, called "a bit of sugar" ???
#sub Iterator (&) { return $_[0] }  #!!Important to make this work uncomment!!!

#HOP page 156
sub make_rand
{
  my $seed = shift || (time & 0x7ffff);
  print "Seed=$seed\n";
  return Iterator {
          #print " << $seed\n";
          $seed = (13  * $seed + 31011) & 0x7ffffff;
          #print " >> $seed\n";
          return $seed;
         };
}


# My test code
my $rng = make_rand();  # a reference to an "Iterator" code different 
                        # from the one defined originally ??

my @bucket;
my $i;
my $t;

#printf " ==%d\n",(2**31);

#  HOP pages 156,7
for $i (1..10000){
  my $rndx = NEXTVAL ($rng);
  #print " $rndx  ";
  $rndx %= 100;
  #print " $rndx\n";
  $bucket[$rndx] ++;
}

# test code
$t=0;
for $i (0..99) {
  print "$bucket[$i]-  ";
  $t+=$bucket[$i];
}
printf "\nAvg= %6.2f\n", $t/100;

__END__