Task

Write a boolean function that tells whether a given integer is prime.



Remember that   1   and all non-positive numbers are not prime.

Use trial division.

Even numbers greater than   2   may be eliminated right away.

A loop from   3   to   √ n    will suffice,   but other loops are allowed.



Related tasks

   count in factors
   prime decomposition
   AKS test for primes
   factors of an integer
   Sieve of Eratosthenes
   factors of a Mersenne number
   trial factoring of a Mersenne number
   partition an integer X into N primes
   sequence of primes by Trial Division


proc is_prime(n)
{
    if n == 2 then
        return true;
    if n <= 1 || n % 2 == 0 then
        return false;
    for i in 3..floor(sqrt(n)):int by 2 do
        if n % i == 0 then
            return false;
    return true;
}