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


function is_prime(integer n)
    if n<=2 or remainder(n,2)=0 then
        return 0
    else
        for i=3 to sqrt(n) by 2 do
            if remainder(n,i)=0 then
                return 0
            end if
        end for
        return 1
    end if
end function