//Make lemonade//Recipe //Number of Cup used to make lemonade public static int CupUsedToMakeLemonade(Recipe recipe, Inventory inventory) { Console.WriteLine("How many cup would you use to make lemonade?"); recipe.numberOfCup = int.Parse(Console.ReadLine()); if (recipe.numberOfCup <= inventory.CountCup()) { return(recipe.numberOfCup); } else { Console.WriteLine("Invalid input."); return(CupUsedToMakeLemonade(recipe, inventory)); } }