std::begin
From cppreference.com
Defined in header <iterator>
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template< class C > auto begin( C& c ) -> decltype(c.begin()); |
(1) | (since C++11) |
template< class C > auto begin( const C& c ) -> decltype(c.begin()); |
(2) | (since C++11) |
template< class T, size_t N > T* begin( T (&array)[N] ); |
(3) | (since C++11) |
Returns an iterator to the beginning of the given container c or array array.
Contents |
[edit] Parameters
c | - | a container with a begin method |
array | - | an array of arbitrary type |
[edit] Return value
an iterator to the beginning of c or array
[edit] Notes
In addition to being included in <iterator>, std::begin is guaranteed to become available if any of the following headers are included: <array>, <deque>, <forward_list>, <list>, <map>, <regex>, <set>, <string>, <unordered_map>, <unordered_set>, and <vector>.
[edit] Specializations
Custom specializations of std::begin may be provided for classes that do not expose a suitable begin() member function, yet can be iterated. The following specializations are already provided by the standard library:
specializes std::begin (function template) | |
(C++11) |
specializes std::begin (function template) |
[edit] Example
#include <iostream> #include <vector> #include <iterator> int main() { std::vector<int> v = { 3, 1, 4 }; auto vi = std::begin(v); std::cout << *vi << '\n'; int a[] = { -5, 10, 15 }; auto ai = std::begin(a); std::cout << *ai << '\n'; }
Output:
3 -5
[edit] See also
(C++11) |
returns an iterator to the end of a container or array (function) |