Declaration vs. Instantiation
===

Comming from Java, I have difficulty with the code below.
In my understanding b is just declared on line 3 but not instantiated.

What would be the text book way of creating an instance of B in class A?

    class A {
      private:
        B b;
      public:
        A() { 
          //instantiate b here?
        }
    };

Edit: What if B does not have a default constructor?
