most expensive type casting in C++?

[Pallav singh]

Q what is the most expensive type casting in C++?

Thanks
Pallav Singh

 

[Victor Bazarov]

Q what is the most expensive type casting in C++?

C-style:

T *ptr = (T*)&some_non_T_object;

It causes uncounted amount of maintenance time spent figuring out what
is wrong when something does go wrong.

V

 

[Balog Pal]

Q what is the most expensive type casting in C++?

Counting runtime cycles, dynamic_cast.

Counting damage due to defects: c-style cast.

 

[Andrey Tarasevich]

Q what is the most expensive type casting in C++?

What's "expensive"? Performance-wise that would be 'dynamic_cast'
performed in "downcast" direction.

 

[red floyd]

Q   what is the most expensive type casting  in C++?

A: http://www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.2

 

[James Kanze]

T *ptr = (T*)&some_non_T_object;

It causes uncounted amount of maintenance time spent figuring
out what is wrong when something does go wrong.

I like that answer. My own answer would have been "the
inappropriate casts". A reinterpret_cast where you really
wanted a static_cast, for example. Or a reinterpret_cast
inserted simply because the code wouldn't compile otherwise
(without the author understanding why). Or a static_cast where
a dynamic_cast would have failed. But then, it doesn't even
occur to me that anyone would use a C style cast for a pointer
or a reference.