What's the difference between class private and public?

Answer 1

Ok! So...
There are three different classes;
Public, private and protected.

Down below is a script I scratched down to easier display.

Classes B, C and D all contain the variables x, y and z. It is just a question of access.

Simply about usage of protected and private access. 

The script:

class A
{
public:
int x;
protected:
int y;
private:
int z;
};

class B : public A
{

// x is public // y is protected // z is not accessible from B }; class C : protected A { // x is protected // y is protected // z is not accessible from C }; class D : private A // 'private' is default for classes { // x is private // y is private // z is not accessible from D };

};

class C : protected A
{
// x is protected // y is protected // z is not accessible from C }; class D : private A // 'private' is default for classes { // x is private // y is private // z is not accessible from D };

};

class D : private A
{
// 'private' is default for classes { // x is private // y is private // z is not accessible from D };

Dr.

Answer 2

A public method or field can be accessed from any object. It's used for entry points into classes, getters and setters, and methods with use outside the class.
A private method or field can only be used within its class. It's used when a method or field doesn't need to be used or modified outside the class.

Answer 3

Good question.

I will answer this shortly, stay tuned. :)