extent Class

Article
01/02/2018

The latest version of this topic can be found at extent Class.

Gets an array dimension.

Syntax

template <class Ty, unsigned I = 0>  
struct extent;

Parameters

Ty
The type to query.

I
The array bound to query.

Remarks

If Ty is an array type that has at least I dimensions, the type query holds the number of elements in the dimension specified by I. If Ty is not an array type or its rank is less than I, or if I is zero and Ty is of type "array of unknown bound of U", the type query holds the value 0.

Example

// std_tr1__type_traits__extent.cpp   
// compile with: /EHsc   
#include <type_traits>   
#include <iostream>   
  
int main()   
    {   
    std::cout << "extent 0 == "   
        << std::extent<int[5][10]>::value << std::endl;   
    std::cout << "extent 1 == "   
        << std::extent<int[5][10], 1>::value << std::endl;   
  
    return (0);   
    }

extent 0 == 5  
extent 1 == 10

Requirements

Header: <type_traits>

Namespace: std