std::array<T,N>::operator[] (3) - Linux Manuals

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

NAME

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

Synopsis

reference operator[]( size_type pos ); (until C++17)
constexpr reference operator[]( size_type pos ); (since C++17)
const_reference operator[]( size_type pos ) const; (until C++14)
constexpr const_reference operator[]( size_type pos ) const; (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.

Example

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