Error Detection and Correction (Ch 5)

Optional: Human Input Validation

Error detection codes are built into many of the numbering systems we use in daily life to prevent simple mistakes. Things like credit card numbers and book ISBNs are designed so that if someone mistypes a digit the error is easily detected.

The basic process for checking a credit card looks like this:

You can try it out by hand with your own card or on this spreadsheet:

Credit Card Validation Spreadsheet

Book ISBN numbers are validated with a stair-step code. If you are interested you can read about how the validation works here.