Initialization list to initialize

There is a class B that inherits subclasses, and their data members are as follows:

ClassA{...Private:ConstIntA;};ClassB:PublicA{...private:   a;public:  const  int b;   a c;   static const < Span class= "KWD" >char* d;   a& e;               



These member variables must be initialized by the constructor initialization list of A or B ()

Parsing: Constants must be initialized in the initialization list, otherwise, because constants can not be modified, any other place as an lvalue will be an error; A::a, b::b is the type, where a::a is overridden by b::a in class B, but B::c must go through class A's initialization list to initialize. The reference type must be initialized so that;a& E is only initialized in the initialization list for this type.

Initialization list to initialize