I previously blogged about this Project Euler puzzle 6 years ago, using ColdFusion. This is my approach using PHP as a simple practical exercise for myself, and I’d appreciate any feedback on my PHP code.

Problem 1:

*If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.*

*Find the sum of all the multiples of 3 or 5 below 1000.*

So not too tricky to start with:

<?php
$sum = 0;
for ($i = 1; $i < 1000; $i++) {
if ($i % 3 == 0 || $i % 5 == 0) {
$sum += $i;
}
}
echo $sum;
?>

The only thing I really noticed was that I could have used *fmod(x, y)* instead of *x % y == 0* to calculate the modulus values, although I didn’t see any benefit in doing so at this point, with such small integers. However it wasn’t long before I had to do so (in the third Project Euler puzzle).

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Pingback by Project Euler redux | Duncan's blog — September 19, 2014 @ 8:04 am |

Something that was pointed out to me early in the piece during my travails into PHP… as a general rule, don’t close your PHP block (“?>”) if it’s the last thing in the file: http://stackoverflow.com/questions/4410704/why-would-one-omit-the-close-tag.

Comment by dacameron — September 19, 2014 @ 10:31 am |

Cool, I’d read this in the PSR-2 coding standard, but didn’t really understand why. I’ll make sure and leave it out from now on!

Comment by duncan — September 19, 2014 @ 10:43 am |