package {

/**
 * Several functions implementing GCD, just for example. This
 * class does not include any logging.
 */ 
public class GCDplain {
  
	/**
	 * Recursive version of GCD. Will not terminate if x or y is 
	 * non-positive, and are unequal.
	 */ 
	public static function recGcd (x:int,y:int) : int {
		var r : int ;
		if (x == y) r = x ;
		else if (x>y) r = recGcd(x-y,y);			
		else r = recGcd(x,y-x);
		return r ;
	}

	/**
	 * Iterative GCD. Will not terminate if x or y is 
	 * non-positive, and are unequal.
	 */ 
	public static function whileGcd (x:int,y:int) : int {
		var iter_count:int = 0
		while (x != y) {
			iter_count++;
			if (x > y) x = x - y;
			else y = y - x ;
		}
		return x;
	}

	/**
	 * Will check the parameters first. If one is non-positive
	 * this function crashes; else it calls the iterative GCD.
	 */ 
	public static function catchGcd (x:int,y:int) : Object  {
		var r : int ;
		try {  
			if (x<=0 || y<=0) throw new Error("oops") ; // crash...
			else r = whileGcd(x,y) ;
		}
		catch (e:Error) {
			var r2 : String =  "check gcd args!" ;
			return r2 ;
		}
		return r ;
	}
}
}