CODEWITHSUNDEEP
c++constexprautodecltype
prasad
prasad

Reputation: 229

use constexpr to determine size of array pointer

I am using constexpr to declare size of std::array.

constexprt auto sizearr = 99;

Based on compile time type deduction on sizearr I want to find type of index used to iterate array

char offset; //Class member

when sizearr changed to

constexprt auto sizearr = 65000;

I want offset to auto declared as type of int instead of changing manually to int.

I am assuming there must be way to mix auto, decltype and constexpr to do this.

Upvotes: 0

Views: 409

Answers (1)

colin
colin

Reputation: 101

Use log2(arraysize)/8 (cast to int) as a non-type template parameter N.

The template is a struct template that defines a type that you need.

Partial specialize based upon value of N.

Upvotes: 0

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