Add organized the vector into header and implementation files

CM2005 Object Oriented Programming/Topic 2/2.6.1/Vec3D.cpp

@@ -0,0 +1,7 @@
+#include <cmath>
+#include "Vec3D.h"
+
+int Vec3D::getLength()
+{
+  return std::sqrt((x*x + y*y + z*z));
+}