std::rank
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header  <type_traits> | ||
| template< class T > struct rank; | (since C++11) | |
If T is an array type, provides the member constant value equal to the number of dimensions of the array. For any other type, value is 0.
| Contents | 
[edit] Helper variable template
| template< class T > constexpr std::size_t rank_v = rank<T>::value; | (since C++17) | |
Inherited from std::integral_constant
Member constants
| value [static] | the number of dimensions of Tor zero(public static member constant) | 
Member functions
| operator std::size_t | converts the object to std::size_t, returns value(public member function) | 
| operator() (C++14) | returns value(public member function) | 
Member types
| Type | Definition | 
| value_type | std::size_t | 
| type | std::integral_constant<std::size_t, value> | 
[edit] Possible implementation
| template<class T> struct rank : public std::integral_constant<std::size_t, 0> {}; template<class T> struct rank<T[]> : public std::integral_constant<std::size_t, rank<T>::value + 1> {}; template<class T, std::size_t N> struct rank<T[N]> : public std::integral_constant<std::size_t, rank<T>::value + 1> {}; | 
[edit] Example
Run this code
Output:
3 4 0
[edit] See also
| (C++11) | checks if a type is an array type (class template) | 
| (C++11) | obtains the size of an array type along a specified dimension (class template) | 
| (C++11) | removes one extent from the given array type (class template) | 
| (C++11) | removes all extents from the given array type (class template) | 
| (library fundamentals TS) | variable template alias of std::rank::value(variable template) | 


