Bitwise operator (aalhour#59)

* Bitwise operator

Using Bitwise operator (&) "r" will recives the modulus result like modulus operator "%" is doing, but is more efficient and fast.

* Comment Bitwise operator

Added a comment to explaing why use bitwise operator.

Algorithms/Numeric/GreatestCommonDivisor.cs

@@ -19,13 +19,17 @@ public static uint FindGCD(uint a, uint b)
                 return a;
 
             uint _a = a, _b = b;
-            uint r = _a % _b;
+
+            //Bitwise operator '&' works on individual bits of each value
+            //result is 0 or 1
+            //it works like a modulus operator '%' but is more efficient
+            uint r = _a & _b;
 
             while(r != 0)
             {
                 _a = _b;
                 _b = r;
-                r = _a % _b;
+                r = _a & _b;
             }
 
             return _b;