Problem Statement

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.

Let's start with the solution:

main:( 
  INT upb=100;
  printf(($" The primes up to "g(-3)" are:"l$,upb));
  FOR i TO upb DO 
    IF is prime(i) THEN
      printf(($g(-4)$,i))
    FI
  OD;
  printf($l$)
)