class foo {
public:
    // Members accessible by everyone
    foo(); // The default constructor.

protected:
    // Members accessible by members, friends, and subclasses
    // Will discuss this when we do advanced OOP in future weeks.

private:
    // Accessible only by members and friends
    void private_member_function();
    int private_data_member_;

public:
    // May define multiple sections of the same name
};