std::end(std::valarray)
| template< class T > /* see below */ end( valarray<T>& v ); |
(1) | (since C++11) |
| template< class T > /* see below */ end( const valarray<T>& v ); |
(2) | (since C++11) |
The overload of std::end for valarray returns an iterator of unspecified type referring to the one past the last element in the numeric array.
- meet the requirements of mutable LegacyRandomAccessIterator,
|
(since C++20) |
- have a member type
value_type, which isT, and - have a member type
reference, which isT&.
- meet the requirements of constant LegacyRandomAccessIterator,
|
(since C++20) |
- have a member type
value_type, which isT, and - have a member type
reference, which isconst T&.
The iterator returned from this function is invalidated when the member function resize() is called on v or when the lifetime of v ends, whichever comes first.
Parameters
| v | - | a numeric array |
Return value
Iterator to one past the last value in the numeric array.
Exceptions
May throw implementation-defined exceptions.
Notes
Unlike other functions that take std::valarray arguments, end() cannot accept the replacement types (such as the types produced by expression templates) that may be returned from expressions involving valarrays: std::end(v1 + v2) is not portable, std::end(std::valarray<T>(v1 + v2)) has to be used instead.
The intent of this function is to allow range for loops to work with valarrays, not to provide container semantics.
Example
#include <algorithm> #include <iostream> #include <valarray> int main() { const std::valarray<char> va { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'C', '+', '+', '!', '\n' }; std::for_each(std::begin(va), std::end(va), [](char c){ std::cout << c; }); }
Output:
Hello, C++!
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2058 | C++11 | 1. end() was required to support replacement types2. it was unspecified when the returned iterators will be invalidated |
1. not required 2. specified |
See also
| (C++11) |
overloads std::begin (function template) |