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

 

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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 the array.

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

Parameters

(none)

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)