Public vs Private (vs Protected)

Alright /prog/, do you prefer to default your class' members to public or private and why?

class dude : person {
public:
　　int var1, var2;
};

or

class dude : person {
　　int var1, var2;
};

>>12
The idea is to retain control over your classes.
Just name your classes as CShitV1_0, CShitV1_1, CShitV1_2, etc.. Every new release can change everything without problem.