TITLE: New cast notation for C++ - const_cast

[ Material taken from "C++ Report", Sept. 94, Vol. 6, No. 7,
  pp 46-51. ]

(continued info on new casts)

This article discusses the new const_cast mechanism, whose
syntax is roughly

	const_cast<T> (expr)

T must be of the type of expr except for the missing const or
volatile. It is an error otherwise:

	class X {};
	class Y : public X {};
	
	const X x;
	Y y = const_cast<y> (x); // error

This is an error because you cannot use this cast mechanism
to convert from an X to a Y. The correct version is

	Y y = (const_cast<Y>)(static_cast<const Y>(x));