# std::default_accessor

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< cpp‎ | container‎ | mdspan

Defined in header `<mdspan>` |  |
template< class ElementType > class default_accessor; |  | (since C++23)

A specialization of `std::default_accessor` class template is the default AccessorPolicy used by std::mdspan if no user-specified accessor policy is provided.

Each specialization of `default_accessor` models `semiregular` and is TriviallyCopyable.

### Template parameters

ElementType | - | the element type. Shall be a complete object type that is neither an abstract class type nor an array type. Otherwise, the program is ill-formed

### Member types

Member type | Definition
`offset_policy` | `default_accessor`
`element_type` | `ElementType`
`reference` | `ElementType&`
`data_handle_type` | `ElementType*`

### Member functions

(constructor) | constructs a `default_accessor` (public member function)
access | returns a nth element provided by arguments (public member function)
offset | returns a data handle advanced by an offset value (public member function)

## std::default_accessor::default_accessor

constexpr default_accessor() noexcept = default; | (1) |
template< class OtherElementType > constexpr default_accessor( default_accessor<OtherElementType> ) noexcept {} | (2) |

1) Default constructs a `default_accessor`.
2) Constructs a `default_accessor` from default_accessor<OtherElementType>. The constructor has no visible effect. This overload participates in overload resolution only if std::is_convertible_v <OtherElementType(*)[], element_type(*)[]> is true.

## std::default_accessor::access

constexpr reference access( data_handle_type p, std::size_t i ) const noexcept; |  |

Equivalent to return p[i];.

## std::default_accessor::offset

constexpr data_handle_type offset( data_handle_type p, std::size_t i ) const noexcept; |  |

Equivalent to return p + i;.

### Example

| This section is incomplete Reason: no example

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