The "const_cast" is not all powerful. It can change the pointer access to a quantity, but the effect of
attempting to change a quantity that is declared "const" is undefined.
Why we use the operator? The reason for this operator is that occasionally you may have a need for value that
is constant most of the time but which can be changed occasionally. For customer or caller, it is a constant,
for implementer, it must be alter on possible occasion. This could be done using the general cast, but the general
cast can also simultaneously change the type.
Many a programmer usually is puzzled by some features of C++ language. Some operator, virual functions, and so on.
Every feature in C++ language is assigned to a purpose.