The point of public/private variables and functions?

Question

This is not a literal coding question, I'm just wondering, what's the point of using public and private functions and variables? Where would I use each of them?

I've always thought of them as being "old" or not needed anymore, but I'm sure there's a good reason they're used in some places.

Answer 1

Basically, when you are developing a class that other developers will use :

• public methods and variables are what the other developers will (need to) use -- what your class does
• private methods and variables are what you, as the developer of that class, used to make it work -- it's how your class works internally.

Others need to be able to use your class ; but not to know how it does it.

If you want to know more, you'll have to search for Encapsulation.