#!/usr/bin/perl -w

use strict;
use warnings;

print CMP("0", $b);
print CMP("", $b);
print CMP("0", "");
print CMP("", "000");
print CMP("", "55");
print CMP("111", "55");
print CMP("8,000,021", "7,999,999");
print CMP("003", "1");
print CMP("001", "2");
print CMP("003", "11");
print CMP("54", "45");
print CMP("123", "32");
print CMP("5", "5");
print CMP("1222225", "001222225");
print CMP("  15", "15");
print CMP("0010", "100");
print CMP("C97F", "C97E");
print CMP("2E", "AE");
print CMP("00101 ", "00101");
exit;


##################################################
#                                      v2020.06.30
# Compares two large positive integers.
# The integers can be binary (ones and zeros),
# octal, decimal, or hexadecimal.
#
# NOTE: Both numbers must be in the same base.
# You shouldn't try to compare a binary number such
# as "10001101" to a hex number like "C4"
# as this will give a bad result.
#
# Returns: 0 if the numbers are equal
#          1 if the first one is greater
#          2 if the second one is greater
#
# Special cases:
# * When comparing an undefined value against
#   an empty string or zero, they will be equal.
# * Minus signs are always ignored!
#
# Usage: INTEGER = CMP(STRING, STRING)
#
sub CMP
{
  my $A = defined $_[0] ? uc($_[0]) : '';
  my $B = defined $_[1] ? uc($_[1]) : '';
  my $A2 = length($A);
  my $B2 = length($B);
  my ($A1, $B1, $CA, $CB, $DIFF) = (0, 0, 48, 48, 0);

  # SHOW WHAT'S HAPPENING:
  print "\n\nString1=|$A|\nString2=|$B|  RET=";

  # Find the first significant digit or starting pointer for each string.
  # We will call this A1 and B1. In case the string starts with zeros,
  # spaces, tabs, new line characters, - and + signs, or other special
  # characters, we skip through those. We ignore them.
  while ($A1 < $A2 && vec($A, $A1, 8) < 49) { $A1++; }
  while ($B1 < $B2 && vec($B, $B1, 8) < 49) { $B1++; }

  # Find last significant digit or ending pointer for each string.
  # We will call this A2 and B2.
  while ($A2 > $A1 && vec($A, --$A2, 8) < 48) {} $A2++;
  while ($B2 > $B1 && vec($B, --$B2, 8) < 48) {} $B2++;

  # Calculate the number of digits in each number.
  my $AL = $A2 - $A1;
  my $BL = $B2 - $B1;

  # Are both numbers the same length?
  if ($AL == $BL)
  {
    # Compare from left to right, incrementing
    # pointers A1 and B1 as we walk through all the digits.
    while ($A1 < $A2)
    {
      $CA = vec($A, $A1++, 8);    # Get digit from string A
      $CB = vec($B, $B1++, 8);    # Get digit from string B
      $DIFF = $CA - $CB;
      if ($DIFF) { return $DIFF < 0 ? 2 : 1; }
    }
    return 0;
  }
  return 1 if ($AL > $BL);
  return 2 if ($AL < $BL);
  return 0;
}