How to use reinterpret_cast in C++?

Question

I know the reinterpret_cast in C++ can be used in this way:

float a = 0;
int b = *reinterpret_cast(&a);

Bu

Answer 1

why cannot cast it directly?

I believe that this is a pure design decision, to make C++ more type-safe than C.

reinterpret_cast is very dangerous, because it can involve type aliasing which is a short way to undefined behavior. When you use C++ casts, you sign a contract with your compiler "I know, what I am doing". So, all these long operators names, angle brackets, type-pointer-type conversions telling you: "Wait, don't do it. Maybe there is something wrong in your code design!".

Also, not all C++ compilers allow type aliasing (either achieved by casting or by unions).