std::array<T,N>::operator[]

 

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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)
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tuple_size<std::array>
tuple_element<std::array>
Deduction guides (C++17)

 

reference operator[]( size_type pos );	(1)	(since C++11) (constexpr since C++17)
const_reference operator[]( size_type pos ) const;	(2)	(since C++11) (constexpr since C++14)

Returns a reference to the element at specified location pos. No bounds checking is performed.

Parameters

pos

-

position of the element to return

Return value

Reference to the requested element.

Complexity

Constant.

Notes

Unlike std::map::operator[], this operator never inserts a new element into the container. Accessing a nonexistent element through this operator is undefined behavior.

Example

The following code uses operator[] to read from and write to a std::array<int, N>:

Run this code

#include <array>
#include <iostream>
 
int main()
{
    std::array<int, 4> numbers{2, 4, 6, 8};
 
    std::cout << "Second element: " << numbers[1] << '\n';
 
    numbers[0] = 5;
 
    std::cout << "All numbers:";
    for (auto i : numbers)
        std::cout << ' ' << i;
    std::cout << '\n';
}

Output:

Second element: 4
All numbers: 5 4 6 8

See also

at	access specified element with bounds checking (public member function)