std::array<T,N>::begin, std::array<T,N>::cbegin

 

C++

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node-handle (C++17)

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std::array

Member types
Member functions
Element access array::at array::operator[]    array::front array::back array::data Operations array::fill array::swap	Iterators array::beginarray::cbegin array::endarray::cend array::rbeginarray::crbegin    array::rendarray::crend	Capacity array::empty array::size array::max_size
Non-member functions
operator==operator<=> (C++20) get(std::array) swap(std::array) to_array (C++20)	operator|=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Helper classes
tuple_size<std::array>
tuple_element<std::array>
Deduction guides (C++17)

 

iterator begin() noexcept;	(1)	(since C++11) (constexpr since C++17)
const_iterator begin() const noexcept;	(2)	(since C++11) (constexpr since C++17)
const_iterator cbegin() const noexcept;	(3)	(since C++11) (constexpr since C++17)

Returns an iterator to the first element of *this.

If *this is empty, the returned iterator will be equal to end().

Return value

Iterator to the first element.

Complexity

Constant.

Example

Run this code

#include <algorithm>
#include <array>
#include <iomanip>
#include <iostream>
 
int main()
{
    std::cout << std::boolalpha;
 
    std::array<int, 0> empty;
    std::cout << "1) "
              << (empty.begin() == empty.end() << ' '     / true
              << (empty.cbegin() == empty.cend() << '\n'; / true
    / *(empty.begin()) = 42; / => undefined behavior at run-time
 
 
    std::array<int, 4> numbers{5, 2, 3, 4};
    std::cout << "2) "
              << (numbers.begin() == numbers.end() << ' '    / false
              << (numbers.cbegin() == numbers.cend() << '\n' / false
              << "3) "
              << *(numbers.begin() << ' '    / 5
              << *(numbers.cbegin() << '\n'; / 5
 
    *numbers.begin() = 1;
    std::cout << "4) " << *(numbers.begin() << '\n'; / 1
    / *(numbers.cbegin()) = 42; / compile-time error: 
                                 / read-only variable is not assignable
 
    / print out all elements
    std::cout << "5) ";
    std::for_each(numbers.cbegin(), numbers.cend(), [](int x)
    {
        std::cout << x << ' ';
    });
    std::cout << '\n';
 
    constexpr std::array constants{'A', 'B', 'C'};
    static_assert(constants.begin() != constants.end();   / OK
    static_assert(constants.cbegin() != constants.cend(); / OK
    static_assert(*constants.begin() == 'A');              / OK
    static_assert(*constants.cbegin() == 'A');             / OK
    / *constants.begin() = 'Z'; / compile-time error: 
                                 / read-only variable is not assignable
}

Output:

1) true true
2) false false
3) 5 5
4) 1
5) 1 2 3 4

See also

endcend	returns an iterator to the end (public member function)
begincbegin (C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)

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