Math::NoCarry - Perl extension for no-carry arithmetic

       brian d foy, "<briandfoy@pobox.com>"

       •   none reported yet :)

       Copyright © 2002-2025, brian d foy <briandfoy@pobox.com>. All rights reserved.

       This  program  is free software; you can redistribute it and/or modify it under the terms of the Artistic
       License 2.0.

perl v5.40.1                                       2025-04-19                                 Math::NoCarry(3pm)

       No-carry arithmetic doesn't allow you to carry digits to the next column. For example, if you add 8 and
       4, you normally expect the answer to be 12, but that 1 digit is a carry.  In no-carry arithmetic you
       can't do that, so the sum of 8 and 4 is just 2. In effect, this is addition modulo 10 in each column. I
       discard all of the carry digits in this example:

                 1234
               + 5678
               ------
                 6802

       For multiplication, the result of pair-wise multiplication of digits is the modulo 10 value of their
       normal, everyday multiplication.

               123
             x 456
             -----
                 8   6 x 3
                2    6 x 2
               6     6 x 1

                5    5 x 3
               0     5 x 2
              5      5 x 1

               2     4 x 3
              8      4 x 2
           + 4       4 x 1
           -------
             43878

       Since multiplication and subtraction are actually types of additions, you can multiply and subtract like
       this as well.

       No carry arithmetic is both associative and commutative.

   Functions
       As of version 1.11, all of these functions are exportable on demand, or with the tag ":all" to get them
       all at once.

       multiply( A, B )
           Returns the no carry product of A and B.

           Return A if it is the only argument ( A x 1 );

       add( A, B )
           Returns the no carry sum of the positive numbers A and B.

           Returns A if it is the only argument ( A + 0 )

           Returns false if either number is negative.

       subtract( A, B )
           Returns the no carry difference of the positive numbers A and B.

           Returns A if it is the only argument ( A - 0 )

           Returns false if either number is negative.

       Math::NoCarry - Perl extension for no-carry arithmetic

       This source is in GitHub:

               https://github.com/briandfoy/math-nocarry

               use Math::NoCarry qw(:all);

               my $sum        = add( 123, 456 );

               my $difference = subtract( 123, 456 );

               my $product    = multiply( 123, 456 );

       •   this could be a full object package with overloaded +, *, and - operators

       •   it would be nice if I could give the functions more than two arguments.

       •   addition and subtraction don't do negative numbers.