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winrt::array_view struct template (C++/WinRT)
A view, or span, of a contiguous series of values. For more examples and info about winrt::array_view, see Standard C++ data types and C++/WinRT.
Syntax
template <typename T>
struct array_view
Template parameters
typename T
The type of the values (elements) that the array_view views, or spans.
Requirements
Minimum supported SDK: Windows SDK version 10.0.17134.0 (Windows 10, version 1803)
Namespace: winrt
Header: %WindowsSdkDir%Include<WindowsTargetPlatformVersion>\cppwinrt\winrt\base.h (included by default)
Member type aliases
| Alias name | Type |
|---|---|
| array_view::value_type | A synonym for the typename T template parameter. |
| array_view::size_type | A synonym for uint32_t. |
| array_view::reference | A synonym for array_view::value_type&. |
| array_view::const_reference | A synonym for array_view::value_type const&. |
| array_view::pointer | A synonym for array_view::value_type*. |
| array_view::const_pointer | A synonym for array_view::value_type const*. |
| array_view::iterator | A synonym for an implementation-defined array iterator of array_view::value_type. |
| array_view::const_iterator | A synonym for an implementation-defined array iterator of array_view::value_type const. |
| array_view::reverse_iterator | A synonym for std::reverse_iterator<array_view::iterator>. |
| array_view::const_reverse_iterator | A synonym for std::reverse_iterator<array_view::const_iterator>. |
Constructors
| Constructor | Description |
|---|---|
| array_view::array_view constructor | Initializes a new instance of the array_view struct as a view over (and not a copy of) the input data. |
Member functions
| Function | Description |
|---|---|
| array_view::at function | Returns a reference to the element at the specified position within the array_view object. |
| array_view::back function | Returns a reference to the last element in the array_view object. |
| array_view::begin function | Returns an iterator to the first element in the array_view object. |
| array_view::cbegin function | Returns a const iterator to the first element in the array_view object. |
| array_view::cend function | Returns a const iterator to one beyond the end of (one beyond the last element in) the array_view object. |
| array_view::crbegin function | Returns a const reverse iterator to one beyond the end of (one beyond the last element in) the array_view object. |
| array_view::crend function | Returns a const reverse iterator to the first element in the array_view object. |
| array_view::data function | Returns a pointer to the underlying data being viewed by the array_view object. |
| array_view::empty function | Returns a value indicating whether the array_view object is empty (is a view on zero elements). |
| array_view::end function | Returns an iterator to one beyond the end of (one beyond the last element in) the array_view object. |
| array_view::front function | Returns a reference to the first element in the array_view object. |
| array_view::rbegin function | Returns a reverse iterator to one beyond the end of (one beyond the last element in) the array_view object. |
| array_view::rend function | Returns a reverse iterator to the first element in the array_view object. |
| array_view::size function | Returns the number of elements in the array_view object. |
Member operators
| Operator | Description |
|---|---|
| array_view::operator[] (subscript operator) | Returns a reference to the element at the specified position within the array_view object. |
Free operators
| Operator | Description |
|---|---|
| operator!= (inequality operator) | Returns a value indicating whether the two parameters are unequal to one another. |
| operator< (less-than operator) | Returns a value indicating whether the first parameter is less than the second parameter. |
| operator<= (less-than-or-equal-to operator) | Returns a value indicating whether the first parameter is less than or equal to the second parameter. |
| operator== (equality operator) | Returns a value indicating whether the two parameters are equal to one another. |
| operator> (greater-than operator) | Returns a value indicating whether the first parameter is greater than the second parameter. |
| operator>= (greater-than-or-equal-to operator) | Returns a value indicating whether the first parameter is greater than or equal to the second parameter. |
Iterators
An array_view is a range, and that range is defined by the array_view::begin and array_view::end member functions, each of which returns an iterator (also see array_view::cbegin and array_view::cend). Because of this, you can enumerate the characters in an array_view object with either a range-based for statement, or with the std::for_each template function.
#include <iostream>
using namespace winrt;
...
template <typename T>
void Iterators(array_view<T> const& theArrayView)
{
for (T& element : theArrayView)
{
std::wcout << element << " ";
}
std::for_each(theArrayView.cbegin(), theArrayView.cend(), [](T const& element) { std::wcout << element << " "; });
}
array_view::array_view constructor
Initializes a new instance of the array_view struct as a view over (and not a copy of) the input data.
Syntax
array_view() noexcept;
template <typename C, uint32_t N> array_view(C(&rawArrayValue)[N]) noexcept;
template <typename C, uint32_t N> array_view(std::array<C, N> const& arrayValue) noexcept;
template <typename C, uint32_t N> array_view(std::array<C, N>& arrayValue) noexcept;
array_view(std::initializer_list<T> initializerListValue) noexcept;
template <typename C> array_view(std::vector<C> const& vectorValue) noexcept;
template <typename C> array_view(std::vector<C>& vectorValue) noexcept;
array_view(T* first, T* last) noexcept;
Template parameters
typename C
The type of the values (elements) in the input data.
uint32_t N
The number of values (elements) in the input data.
Parameters
rawArrayValue
A raw array value that initializes the array_view object.
arrayValue
A std::array value that initializes the array_view object.
initializerListValue
An initializer list value that initializes the array_view object.
vectorValue
A std::vector value that initializes the array_view object.
first last
Pointers to values with which to initialize the array_view object. If first equals last, then the array_view object is empty.
Example
using namespace winrt;
...
void Constructors()
{
// array_view() noexcept
array_view<byte const> fromDefault{};
byte theRawArray[]{ 99, 98, 97 };
// template <typename C, uint32_t N> array_view(C(&value)[N]) noexcept
array_view<byte const> fromRawArray{ theRawArray };
const std::array<byte, 3> theConstArray{ 99, 98, 97 };
// template <typename C, uint32_t N> array_view(std::array<C, N>& value) noexcept
array_view<byte const> fromConstArray{ theConstArray };
std::array<byte, 3> theArray{ 99, 98, 97 };
// template <typename C, uint32_t N> array_view(std::array<C, N> const& value) noexcept
array_view<byte const> fromArray{ theArray };
// array_view(std::initializer_list<T> value) noexcept
array_view<byte const> fromInitializerList{ 99, 98, 97 };
const std::vector<byte> theConstVector{ 99, 98, 97 };
// template <typename C> array_view(std::vector<C> const& value) noexcept
array_view<byte const> fromConstVector{ theConstVector };
std::vector<byte> theVector{ 99, 98, 97 };
// template <typename C> array_view(std::vector<C>& value) noexcept
array_view<byte const> fromVector{ theVector };
// array_view(T* first, T* last) noexcept
array_view<byte const> fromRange{ theArray.data(), theArray.data() + 2 }; // just the first two elements.
}
array_view::at function
Returns a reference to the element at the specified position within the array_view object.
Syntax
T& at(uint32_t const pos);
T const& at(uint32_t const pos) const;
Parameters
pos
A zero-based element position, or index.
Return value
A reference to the element at the specified position within the array_view object.
array_view::back function
Returns a reference to the last element in the array_view object.
Syntax
T const& back() const noexcept;
T& back() noexcept;
Return value
A reference to the last element in the array_view object.
array_view::begin function
Returns an iterator to the first element in the array_view object. See Iterators.
Syntax
stdext::checked_array_iterator<T const> begin() const noexcept;
stdext::checked_array_iterator<T> begin() noexcept;
Return value
An iterator to the first element in the array_view object.
array_view::cbegin function
Returns a const iterator to the first element in the array_view object. See Iterators.
Syntax
stdext::checked_array_iterator<T const> cbegin() const noexcept;
Return value
A const iterator to the first element in the array_view object.
array_view::cend function
Returns a const iterator to one beyond the end of (one beyond the last element in) the array_view object. See Iterators.
Syntax
stdext::checked_array_iterator<T const> cend() const noexcept;
Return value
A const iterator to one beyond the end of (one beyond the last element in) the array_view object.
array_view::crbegin function
Returns a const reverse iterator to one beyond the end of (one beyond the last element in) the array_view object.
Syntax
std::reverse_iterator<stdext::checked_array_iterator<T const>> crbegin() const noexcept;
Return value
A const reverse iterator to one beyond the end of (one beyond the last element in) the array_view object.
array_view::crend function
Returns a const reverse iterator to the first element in the array_view object.
Syntax
std::reverse_iterator<stdext::checked_array_iterator<T const>> crend() const noexcept;
Return value
A const reverse iterator to the first element in the array_view object.
array_view::data function
Returns a pointer to the underlying data being viewed by the array_view object.
Syntax
T const* data() const noexcept;
T* data() noexcept;
Return value
A pointer to the underlying data being viewed by the array_view object.
array_view::empty function
Returns a value indicating whether the array_view object is empty (is a view on zero elements).
Syntax
bool empty() const noexcept;
Return value
true if the array_view object is empty (is a view on zero elements), otherwise false.
array_view::end function
Returns an iterator to one beyond the end of (one beyond the last element in) the array_view object. See Iterators.
Syntax
stdext::checked_array_iterator<T const> end() const noexcept;
stdext::checked_array_iterator<T> end() noexcept;
Return value
An iterator to one beyond the end of (one beyond the last element in) the array_view object.
array_view::front function
Returns a reference to the first element in the array_view object.
Syntax
T const& front() const noexcept;
T& front() noexcept;
Return value
A reference to the first element in the array_view object.
array_view::operator[] (subscript operator)
Returns a reference to the element at the specified position within the array_view object.
Syntax
T const& operator[](uint32_t const pos) const noexcept;
T& operator[](uint32_t const pos) noexcept;
Parameters
pos
A zero-based element position, or index.
Return value
A reference to the element at the specified position within the array_view object.
array_view::rbegin function
Returns a reverse iterator to one beyond the end of (one beyond the last element in) the array_view object.
Syntax
std::reverse_iterator<stdext::checked_array_iterator<T const>> rbegin() const noexcept;
std::reverse_iterator<stdext::checked_array_iterator<T>> rbegin() noexcept;
Return value
A reverse iterator to one beyond the end of (one beyond the last element in) the array_view object.
array_view::rend function
Returns a reverse iterator to the first element in the array_view object.
Syntax
std::reverse_iterator<stdext::checked_array_iterator<T const>> rend() const noexcept;
std::reverse_iterator<stdext::checked_array_iterator<T>> rend() noexcept;
Return value
A reverse iterator to the first element in the array_view object.
array_view::size function
Returns the number of elements in the array_view object.
Syntax
uint32_t size() const noexcept;
Return value
A uint32_t containing the number of elements in the array_view object.
operator!= (inequality operator)
Returns a value indicating whether the two parameters are unequal to one another.
Syntax
template <typename T> bool operator!=(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the two parameters are unequal to one another, otherwise false.
operator< (less-than operator)
Returns a value indicating whether the first parameter is less than the second parameter.
Syntax
template <typename T> bool operator<(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the first parameter is less than the second parameter, otherwise false.
operator<= (less-than-or-equal-to operator)
Returns a value indicating whether the first parameter is less than or equal to the second parameter.
Syntax
template <typename T> bool operator<=(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the first parameter is less than or equal to the second parameter, otherwise false.
operator== (equality operator)
Returns a value indicating whether the two parameters are equal to one another.
Syntax
template <typename T> bool operator==(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the two parameters are equal to one another, otherwise false.
operator> (greater-than operator)
Returns a value indicating whether the first parameter is greater than the second parameter.
Syntax
template <typename T> bool operator>(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the first parameter is greater than the second parameter, otherwise false.
operator>= (greater-than-or-equal-to operator)
Returns a value indicating whether the first parameter is greater than or equal to the second parameter.
Syntax
template <typename T> bool operator>=(winrt::array_view<T> const& left, winrt::array_view<T> const& right) noexcept;
Parameters
left right
An array_view value to compare with the other parameter.
Return value
true if the first parameter is greater than or equal to the second parameter, otherwise false.
See also
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