What is the need of private access specifier ??

Question

I mean ,we can use public access specifier alone,so we can call the data,functions out of class everytime..why using private access specifier which is access only inside the class??

Answer 1

It's part of data hiding concept. You mostly write classes/structs that you and others will use and implementation of functiond and types of data may change. Thus what people usually do if there's a data member that must be exposed to the outside world is : they make the member private and write a getter/setter method for it (pretty much just a return statement but if needed it can be expanded lster).
Especially useful in terms of setters. It is just a simple member function which accepts a parameter of the desired data member and sets it's value to match the parameters. Also, this setter can be improved or secured with your own logic (like: if you have a Player object and want to .SetHP above 100 it will eventually set it to 100).

It's not mandatory and is purely comlile-time checked so does NOT provides any security runtime BUT helps your fellow programmers.

Answer 2

because you want to hide the data and you can provide functions to reach them outdide from class, but you cant see the field itself