output.txt

primality test using primality_naive(int64_t)
L = 100000 : R = 200000
test 1 duration : 19.897 s
test 2 duration : 20.491 s
average of 2 test(s) : 20.198 s

primality_naive.cpp

bool primality_naive(int64_t a) {
    int c = 0;
    for(int i = 1; i <= a; i++)
        if(a % i == 0) {
            c++;
            if(c > 2)
                return false;
        }
    if(c == 2)
        return true;
    return false;
}