// Lang_28 [virtual functions].nova


// The application class.
class VirtualFunctionsApp
{
   // Application class's "main" function.
   public static void main( String[] args )
   {
      A a = new A( ), c = new C( );

      Stream.writeLine( a.toString( ) );

      Stream.writeLine( c.toString( ) );

      Stream.writeLine( c.baseMethod( ) );
   }
}


class A
{
   public virtual String toString( )
   {
      return "A.toString( )";
   }

   public virtual A test1( )
   {
      return this;
   }

   public String baseMethod( )
   {
      // Call a local virtual method.
      return toString( );
   }
}


class B : A
{
   public String toString( )
   {
      return "B.toString( )";
   }

   // Overloaded virtual method with covariant return type.
   public B test1( )
   {
      return this;
   }

   public virtual void test2( )
   {
   }
}


class C : B
{
   public String toString( )
   {
      return "C.toString( )";
   }

   // Overloaded virtual method with covariant return type.
   public C test1( )
   {
      return this;
   }
}