Item 2:Prefer C++-style casts.(More Effective C++)

static_cast has basically the same power and meaning as the general-purpose C-style cast. It also has the same kind of restrictions. For example, you can't cast a struct into an int or a double into a pointer using static_cast any more than you can with a C-style cast. Furthermore, static_cast can't remove constness from an expression, because another new cast, const_cast, is designed specifically to do that.

The other new C++ casts are used for more restricted purposes. const_cast is used to cast away the constness or volatileness of an expression. By using a const_cast, you emphasize (to both humans and compilers) that the only thing you want to change through the cast is the constness or volatileness of something. This meaning is enforced by compilers.