The Labs.Com Issue_04_Randomness

TPJ: Issue_04_Randomness

This is a collection of programs published by The Perl Journal. You can download all source-code also from TPJ: Programs.

1. ansirand
2. lfsr
3. More Samples on Randomness

Download ansirand

#!/usr/bin/perl -w

use Config;

print "Your random number generator repeats itself after\n";

print "no more than ", 2 ** $Config{randbits}, " numbers.\n";

srand(1);

if (int(rand() * (2 ** $Config{randbits})) == 16838) {

print "Uh oh!  Looks like your computer uses the ANSI example.\n";

print "I bet the next three numbers are 5758, 10113, and 17515.\n"\

;

foreach (1,2,3) {

print rand() * (2 ** $Config{randbits}), "\n";

}

}

Issue_04_Randomness 2. lfsr

Download lfsr

#!/usr/bin/perl -w

$seed = dec2bin(shift);

@array = split('', $seed);

@xor_bits = @ARGV;

splice(@array, 0, 31-$ARGV[0]);

print "@array\n";

while (1) {

getc();

$new_bit = 0 + $array[0];

foreach (@xor_bits[1..$#xor_bits]) {

$new_bit ^= $array[$#array - $_];

}

print pop @array;

unshift (@array, $new_bit);

}

sub dec2bin { unpack("B*", pack("N", shift)) }

Issue_04_Randomness 3. More Samples on Randomness

• Issue_04_Randomness