public Purchase InputPurchase() { { Console.WriteLine(INPUT_TYPE); string type = inputer.InputStrings(); Console.WriteLine(INPUT_NAME); string name = inputer.InputStrings(); Console.WriteLine(INPUT_QUANTITY); int quantity = inputer.InputQuantity(); if (quantity.GetType() != typeof(Int32)) { throw new FormatException(); } if (quantity < 0) { throw new NegativeQuantityException(NEGATIVE_QUANTITY_EXCEPTION); } Console.WriteLine(INPUT_PRICE); decimal price = inputer.InputPrice(); if (price.GetType() != typeof(Decimal)) { throw new FormatException(); } if (price < 0) { throw new NegativePriceException(NEGATIVE_PRICE_EXCEPTION); } Purchase purchase = new Purchase(type, name, quantity, price); return(purchase); } }