Even if you have these functions you do not always want to give these functions individually, because there might be some constraints between the values which have to be preserved and you can preserve those by controlling access to them.
अशाप्रकारे फंक्शन असले तरी, आपण ते नेहमीच स्वतंत्रपणे वापरणार नाही. कारण काही वेळेला व्हॅल्यू राखून ठेवण्याबद्दल काही कंसट्रेन असतात.