• (nodebb)

    Your so called "credit card number" is not actually a number; it is a digit string. And the last four digits are also a digit string.

    I've been saying this or things like it for yonks and yonks and yonks and YONKS.

  • (nodebb)

    Arithmetic and mathematics are not the same thing. The inability to do arithmetic accurately is not an indication that you can't do (or teach) calculus - or vice versa.

  • Die Kuhe (kein roboter) (unregistered)

    Considering the last four digits as number is not necessarily wrong: when the user inputs "0000" it's read as number 0, and comparing it with a stored number 0 should work as expected. The details depend of course on what they actually do with the data.

  • Spencer (unregistered)

    The last 4 digits of the card are 0. It's technically correct.

  • (nodebb) in reply to jeremypnet

    People with math degrees are well known for not being able to do basic arithmetic.

  • Randal L. Schwartz (github)

    Just wait until the last for digits are 0009 and you get a "bad octal conversion" error. :)

  • Die Kuhe (kein roboter) (unregistered) in reply to Randal L. Schwartz

    Not necessarily. It depends on whether you scanf it as %i or %d.

  • (nodebb) in reply to Dragnslcr

    This is because "basic arithmetic" is actually quite scary when you start to do advanced maths and run across things like Godel's incompleteness theorem and such fun things as 1 - 1/2 + 1/3 - 1/4 + 1/5 .... can be take any value you feel like (and there's plenty more infinite series like that).

  • Eric (unregistered)

    One possibility: The denominators were summed correctly but displayed incorrectly. That 0.75/0.75 was meant to be 0.75/2, but they put the numerator twice.

    My mum once had a list of credit card numbers in a spreadsheet. Excel thought 15 significant figures is enough for any ordinary number, so it dropped the last digit. Fortunately credit card numbers have one redundant digit and I quickly had a script to restore them.

  • (nodebb)

    Odd coincidence. I received a replacement credit card in the mail yesterday. It ends in "0000".

    I'm old and have had umpteen dozen credit cards over the decades. None ending in "0000". I wonder what amazing WTF's I'll be sending in soon?

  • Die Kuhe (kein roboter) (unregistered) in reply to WTFGuy

    Speaking about exact math...

    How funny. It only happens to one cord out of 30 or 40. Or maybe even more seldom! ;-)

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