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# std::begin

From cppreference.com
< cpp‎ | iterator

Defined in header `<iterator>` |  |
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()); | (1) | (since C++11)
template< class T, size_t N > T* begin( T (&array)[N] ); | (2) | (since C++11)
template< class C > auto cbegin( const C& c ) -> decltype(std::begin(c)); | (3) | (since C++14)

Returns an iterator to the beginning of the given container `c` or array `array`.

1) Returns a possibly const-qualified iterator to the beginning of the container `c`.
2) Returns a pointer to the beginning of the array `array`.
3) Returns a const-qualified iterator to the beginning of the container `c`.

### [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:

std::begin(std::initializer_list) (C++11) | specializes std::begin (function template) [edit]
std::begin(std::valarray) (C++11) | specializes std::begin (function template) [edit]

### [edit] Example

Run this code

    #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

end cend (C++11)(C++14) | returns an iterator to the end of a container or array (function) [edit]

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