c++ - Calculate some values using template size_t param -

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• template metaprogramming - difference between using enum hack , static const 3 answers

what c++ way calculate values using template params?

template<typename t, size_t size> class threadsafearray { private:     static const size_t block_size = size > 32 ? 16 : 4;     static const size_t mutex_count = size / block_size + 1;     ... }; 

or this

template<typename t, size_t size> class threadsafearray { private:     enum     {         block_size = size > 32 ? 16 : 4,         mutex_count = size / block_size + 1     };         .... }; 

or somehow else?

the enum hack old way provide compile-time computations. used when in class initialization not supportted compilers, static const cannot used. nowadays fixed in modern compilers. preferred way use static const.

check this answer more info.