Timeline for Credit card validation
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 12, 2017 at 7:31 | history | edited | CommunityBot |
replaced http://programmers.stackexchange.com/ with https://softwareengineering.stackexchange.com/
|
|
| Aug 16, 2015 at 15:27 | comment | added | CodesInChaos |
999 999 999 999 999 has 15 digits, but when I run it I get 16. Using (int)floor(log10(n)) + 1.
|
|
| Aug 16, 2015 at 14:59 | comment | added | CodesInChaos |
Even without floating point errors your code is wrong, ceil(log10(10)) == 1 and ceil(log10(9)) == 0. The "correct" formula would be (int)floot(Log10(n)) + 1
|
|
| Aug 16, 2015 at 14:51 | comment | added | CodesInChaos |
I'm not a fan on the log10 approach since you'd need to be sure that floating point rounding errors won't lead to an off-by-one error. AFAIK the IEEE guaranteed for transcendental functions are relatively weak and C's guarantees might be even weaker. In addition to that, 16 digits corresponds to 53.15 bits, so you won't even be able to represent some of them exactly as double.
|
|
| Aug 16, 2015 at 10:59 | comment | added | Caridorc | @StefanRendevski :) thanks for knowing the rules | |
| Aug 16, 2015 at 10:54 | comment | added | Stefan Rendevski | @Caridorc I meant I updated my file, not the code posted in this question. Sorry for the misunderstanding. | |
| Aug 16, 2015 at 8:06 | comment | added | Caridorc | @StefanRendevski Never change code in question. Ask another question after implementing the improvments | |
| Aug 16, 2015 at 0:18 | comment | added | Stefan Rendevski |
Updated the code with some of your suggestions. The function sprintf wasn't covered in the lectures, so I'll leave that out for now. Since I cannot use functions, is the ceil(log10(credit_card)) more readable than my for loop when it comes to calculating the number of digits?
|
|
| Aug 15, 2015 at 22:05 | vote | accept | Stefan Rendevski | ||
| Aug 15, 2015 at 21:59 | review | First posts | |||
| Aug 15, 2015 at 22:03 | |||||
| Aug 15, 2015 at 21:57 | history | answered | Obenland | CC BY-SA 3.0 |