RosettaCodeData/Task/Primality-by-trial-division/D/primality-by-trial-division-3.d
2014-04-02 16:56:35 +00:00

15 lines
405 B
D

import std.stdio, std.algorithm, std.range, std.math;
bool isPrime3(T)(in T n) pure nothrow {
if (n % 2 == 0 || n <= 1)
return n == 2;
T head = 3, tail = (cast(T)real(n).sqrt / 2) * 2 + 1;
for ( ; head <= tail ; head +=2, tail -= 2)
if ((n % head) == 0 || (n % tail) == 0)
return false;
return true;
}
void main() {
iota(2, 40).filter!isPrime3.writeln;
}