The data types the 4 different casts can take (or normally take) in c++
It seems static_cast take could take value, reference or pointer and convert them to another type of value, reference or pointer. However, it seems dynamic_cast, reinterpret_cast and const_cast can only take reference and pointer .
I know for cont_cast, it only take pointer or reference but not variable which is undefined behavior. Not sure why dynamic_cast and reinterpret_cast can only take reference and pointer and what will happen if use dynamic_cast and reinterpret_cast on value types.
For instance, static_cast take could take pointer :
B* pb; D* pd;
pointer:D* pd2 = static_cast<D*>(pb); // Not safe, D can have fields and methods that are not in B.
For another instance, suppose dynamic_cast and reinterpret_cast take value types:
int B; char D;
B = dynamic_cast<B>(D);
int B; char D;
B = reinterpret_cast<B>(D);
What will happen and why we should not do this?
However, it is not safe for static_cast to take pointer as input
The point of static cast is that it uses compile-time information to determine if the cast is safe. So you certainly can convert pointers using static_cast:
struct A {};
struct B : A {};
int main() {
B * bp = nullptr;
A * ap = static_cast <A*> (bp); // OK
char * cp = static_cast <char*> (bp); // error
}