Re: Binding

On Jul 30, 6:04 pm, Tom Gur <gur....@gmail.com> wrote:


In a very general sense, "binding time" refers to the time where
identifiers/variables are bound to values. Early binding, also called
"static binding" or "compile time binding" refers to the fact that
identifiers get bound to the values at compile time. Run-time
binding / dynamic binding / late binding refers to the fact that the
binding is delayed till run time.

of course, 'Binding' should not be confused with 'changing the
value' .

In C++, virtual functions follow late binding. Non virtual functions
follow early binding. On the other hand, all variables are _always_
early bound. This can be seen from the following example:

struct A
{
   int i;
   A() : i(10) { }
   virtual void foo();
};

struct B: public A
{
    int i;
    B(): i(20) { }
    void foo();
};

int main()
{
    A* a = new B();
    int s = a->i; // value of s is 10 not 20 : early binding
    a->foo(); // calls B::foo() : late binding
}

-N