These are chat archives for camperbot/bonfire-sum-all-primes

7th
Oct 2016
Dailan Chang
@Onesupon
Oct 07 2016 06:10
Excuse me

function getPrimes(max) {
var sieve = [];
var i;
var j;
var primes = [];
for (i = 2; i <= max; ++i) {
if (!sieve[i]) {
// i has not been marked -- it is prime
primes.push(i);
for (j = i << 1; j <= max; j += i) {
sieve[j] = true;
}
}
}

return primes;

}

I cannot figure out how the prime works
how can the function determine which numbers between 2~the max num is a prime
I understand it start from 2
but is it ++i equals to i++?