add forward declaration examples

add class & inheritance examples

CPlusPlus/Classes/main.cpp

@@ -0,0 +1,27 @@
+#include <iostream>
+
+#include "Entity.h"
+#include "Ork.h"
+#include "Vector3.h"
+
+using namespace std;
+
+int main()
+{
+	Entity entity; // this is an entity instance
+	entity.name = "My Entity";
+
+	//Monster monster; // can't be instantiated, because Monster is abstract
+
+	Ork ork;
+	ork.name = "My Ork";
+	ork.Move();
+
+	cout << entity.ToString() << endl;
+	cout << ork.ToString() << endl;
+
+	Vector3 position(1.0f, 3.0f, -5.0f);
+	position.y = 0.0f;
+
+	return 0;
+}