virtual function question

[Angus Leeming]

I think I've read (I can't find where I've read it) that Bar is "better" than 
Foo, but I don't know why and it's bugging me ;-)

Could someone explain?
Angus

class Foo {
public:
        virtual ~Foo() {}
        virtual void foo() = 0;
};

class Bar {
public:
        virtual ~Bar() {}
        void bar() { bar_private(); }
private:
        virtual void bar_private() = 0;
}