Static hi(static: members) members of a class can be used without having
available an object of their class. Public static members can be called like
free functions, albeit that their class names must be specified when they are
called.

Assume a class tt(String) has a public static member function
tt(count), returning the number of string objects created so
far. Then, without using any tt(String) object the function
tt(String::count) may be called:
        verb(    void fun()
    {
        cout << String::count() << '\n';
    })

em(Public) static members can be called like free functions (but see also
section ref(CALLINGCONVENTION)).  em(Private) static members can only be
called within the context of their class, by their class's member or friend
functions.

    Since static members have no associated objects their addresses can be
stored in ordinary function pointer variables, operating at the global
level. Pointers to members cannot be used to store addresses of static
members. Example:
        verb(    void fun()
    {
        size_t (*pf)() = String::count;
                // initialize pf with the address of a static member function

        cout << (*pf)() << '\n';
                // displays the value returned by String::count()
    })

