public double GetSalesPrice(double qty, Product product, string unit) { double qtyInProductUnit = 0; switch (unit) { case "kg": qtyInProductUnit = mu.ConvertFromKilograms(qty, product.GetUnit()); break; case "g": qtyInProductUnit = mu.ConvertFromGrams(qty, product.GetUnit()); break; case "lb": qtyInProductUnit = mu.ConvertFromLBs(qty, product.GetUnit()); break; case "oz": qtyInProductUnit = mu.ConvertFromOunces(qty, product.GetUnit()); break; } return(qtyInProductUnit * product.GetPrice()); }