Wednesday, August 5, 2009

Determine Whether Number is a Prime Number 


function isPrime(num) {
  for (var i=(num-1); i > 1; i--) {
    if ((num % i) == 0) {
      return false;
    }
  }
  return true;
}

trace(isPrime(2)); //Outputs true
trace(isPrime(4)); //Outputs false
trace(isPrime(17)); //Outputs true
at

1 comment:

  1. AnonymousSeptember 1, 2011 at 4:39 AM

    One small issue with this, it returns true for 1, where 1 is not prime. If the following clause is added it seems to work great:

    if (num == 1) return false;

    Thanks for the code! :-)

    rob

    ReplyDelete