# std::counted_iterator<I>::operator[]

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< cpp‎ | iterator‎ | counted iterator

constexpr decltype(auto) operator[]( std::iter_difference_t<I> n ) const requires std::random_access_iterator<I>; |  | (since C++20)

Accesses the element at specified relative location. The behavior is undefined if `n` is not less than the recorded distance to the end.

### Parameters

n | - | position relative to current location

### Return value

this->base()[n].

### Example

Run this code

    #include <iostream>
    #include <iterator>
    #include <array>
    #include <list>

    int main()
    {
        std::array array{'A', 'B', 'C', 'D', 'E'};

        std::counted_iterator it{ array.begin() + 1, /*count:*/ 3 };

        for (int i{}; i != it.count(); ++i)
            std::cout << it[i] << ' ';
        std::cout << '\n';

        for (int i{}; i != it.count(); ++i)
            it[i] += ('E' - 'A');

        for (int i{}; i != it.count(); ++i)
            std::cout << it[i] << ' ';
        std::cout << '\n';

        std::list list {'X', 'Y', 'Z', 'W'};
        std::counted_iterator it2{ list.begin(), 3 };
    //  char x = it2[0]; // Error: requirement `random_access_iterator` was not satisfied.
        std::cout << *it2 << '\n'; // OK
    }

Output:

    B C D
    F G H
    X

### See also

operator*operator-> (C++20) | accesses the pointed-to element (public member function)

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