Jochem Maas wrote: > Brian P. Giroux wrote: >> I am just learning PHP and as a practical exercise I've been working on >> a set of functions to process and manipulate what I call "normalized >> number" (ISBNs, EANs, UPCs, etc...) >> >> My ultimate goal is to create a normnum class and child classes for the >> different types of numbers. >> >> Because of my line of work, I am mostly interested in ISBN-10s, >> ISBN-13s, EANs and UPCs, but it can also be expanded to credit card >> numbers, Canadian Social Insurance Numbers, and many more. >> >> So far I have functions to validate ISBN-10s and EANs although I've run >> into a bit of a wall with the digit_sum function as explained in the B: >> section of that functions header comments. > > if you want to turn the direction around reverse the string before > you start the loop: > http://php.net/manual/en/function.strrev.php I never thought of turning the string around. > personally I would turn the string into an array of chars (which you can then also > reverse as need be) and then do a foreach loop on it ('array index'+1 can be used > to determine position) ... personal preference. anyway take a look at these functions: Is there a reason for converting to an array. It seems to me that the conversion would add more overhead. > http://php.net/manual/en/function.str-split.php > http://php.net/array_reverse > http://php.net/foreach >> If anyone can help me out with that or provide any other advice about >> the rest of it, I'd be grateful. > > keep commenting all your code to that extent! you do us proud :-) Thanks, I don't have much choice. I can only work on this every few days, sometimes every few weeks. If I don't comment I find that I forget what I was doing :( Thanks for your input. >> The file can be found at http://www.senecal.ca/normnums.php.txt >> >> Thanks. -- Brian P. Giroux -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
