Programming, Swift, Object Oriented, Objective C.
canvas) { canvas->draw(canvas); } // Base implementation of drawing void _CanvasDraw(struct Canvas *canvas) { printf("width: %d, height: %d\n", canvas->width, canvas->height); } // Overriden implementation void _DisplayCanvasDraw(struct DisplayCanvas *canvas) { printf("width: %d, height: %d, color