How can I test for primality?

Question

I am writing a little library with some prime number related methods. As I\'ve done the groundwork (aka working methods) and now I\'m looking for some optimization. Ofcours

Answer 1

Your for loop should look like this:

for (int idx = 3; idx * idx <= test; idx++) { ... }

That way, you avoid floating-point computation. Should run faster and it'll be more accurate. This is why the for statement conditional is simply a boolean expression: it makes things like this possible.