Rectangle::Rectangle(double w, double l) {
   setWidth(w);
   setLength(l);
}

double Rectangle::perimeter(void) { 
   return 2 * (width + length); 
}

double Rectangle::area(void) { 
   return width * length; 
}

void Rectangle::setWidth(double w) { 
   width = w;
}

void Rectangle::setLength(double l) { 
   length = l;
}

double Rectangle::getWidth(void) const { 
   return width; 
}

double Rectangle::getLength(void) const { 
   return length; 
}