fn is_prime(num: u64) -> bool {
    for i in 2..num {
        if num % i == 0 {
            return false;
        }
    }
    true
}
// checks whether a number is prime, slowly
checks whether a number is prime, slowly
checks whether a number is prime slowly
fn is_prime(num: u64) -> bool {
    for i in 2..num {
        if num % i == 0 {
            return false;
        }
    }
    true
}
fn is_prime ( num : u64 ) -> bool { for i in 2 .. num { if num % i == 0 { return false ; } } true }
checks whether a number is prime, slowly
checks whether a number is prime slowly
num
u64
num
u64