E-Commerce Tip: Programmatically Validate Credit Card Numbers Los Angeles CA

Employ this function in your e-commerce application to validate the credit card numbers your users enter.

Local Companies

Moyea Software
92295612365
Hot building, ring street
LA, CA
Interneer Inc.
8005586832 x85
6101 W. Centinela Ave.
Culver City, CA
Cornerstone Concepts Inc
818-247-3909
600 W Broadway
Glendale, CA
Greene Computer Corporation
(818) 956-4961
200 S. Louise Street
Glendale, CA
Corticalx Inc Software Solutions & Technology
818-500-0881
425 E Colorado St
Glendale, CA
Alphatier Systems
818-409-8920
517 Griswold St
Glendale, CA
TimeTECH - Customizable Time and Attendance / Workforce Management Solutions
905-677-7009
7420 Airport Rd 203
Mississauga, CA
Hutchinson & Bloodgood, LLP
(818) 637-5000
101 N. Brand Blvd. #1600
Glendale, CA
Telsoft Solutions
818-545-8680
100 N Brand Blvd
Glendale, CA
Abraxas Technologies Inc
818-502-9100
450 N Brand Blvd
Glendale, CA

provided by: 
Originally published at Internet.com


Before I accept any credit card number into my application, I run a simple numerical validation against it. All major credit cards (American Express, Discover, MasterCard, and Visa) use the Luhn algorithm to validate the numbers—why not you? Although this function doesn't go the extra step of actually running the card to see if the transaction will work, it will give you a simple true/false result regarding the card number's validity. The function also ignores all non-digit characters, so your users can enter the number however they wish.

This is the function to run the algorithm on a given string of numbers: ///

/// Validates a credit card number using the standard Luhn/mod10 /// validation algorithm. /// /// Card number, with or without /// punctuation /// True if card number appears valid, false if not /// public bool IsCreditCardValid(string cardNumber) { const string allowed = "0123456789"; int i; StringBuilder cleanNumber = new StringBuilder(); for (i = 0; i < cardNumber.Length; i++) { if (allowed.IndexOf(cardNumber.Substring(i, 1)) >= 0) cleanNumber.Append(cardNumber.Substring(i, 1)); } if (cleanNumber.Length < 13 || cleanNumber.Length > 16) return false; for (i = cleanNumber.Length + 1; i <= 16; i++) cleanNumber.Insert(0, "0"); int multiplier, digit, sum, total = 0; string number = cleanNumber.ToString(); for (i = 1; i <= 16; i++) { multiplier = 1 + (i % 2); digit = int.Parse(number.Substring(i - 1, 1)); sum = digit * multiplier; if (sum > 9) sum -= 9; total += sum; } return (total % 10 == 0); }

About the Author

Eric Smith is the owner of Northstar Computer Systems, a Web-hosting company based in Indianapolis, Indiana. He is also a MCT and MCSD who has been developing with .NET since 2001. In addition, he has written or contributed to 12 books covering .NET, ASP, and Visual Basic.

Author: Eric Smith

Read article at Internet.com site

Featured Local Company

Moyea Software

92295612365
Hot building, ring street
LA, CA

Related Local Events
Automation Technology Expo West (ATX West)
Dates: 2/9/2010 - 2/11/2010
Location: Anaheim Convention Center
Anaheim, CA
View Details

SOLAR POWER - Exhibition and Conference
Dates: 10/12/2010 - 10/14/2010
Location: Los Angeles Convention & Exhibition Center
Los Angeles, CA
View Details

REAL-TIME & EMBEDDED COMPUTING CONFERENCE - LONG BEACH 2009
Dates: 10/1/2009 - 10/1/2009
Location: Marriott Long Beach
Long Beach, CA
View Details

2009 IEEE Petroleum and Chemical Industry Technical Conference (PCIC 2009)
Dates: 9/14/2009 - 9/16/2009
Location:
Anaheim, CA
View Details

Medical Design & Manufacturing - Trade
Dates: 6/9/2009 - 6/11/2009
Location: CANON COMMUNICATIONS LLC
Los Angeles, CA
View Details