# operator==(std::counted_iterator<I>, std::default_sentinel_t)

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< cpp‎ | iterator‎ | counted iterator

friend constexpr bool operator==( const counted_iterator& x, std::default_sentinel_t ); |  | (since C++20)

Checks if the underlying length (i.e. distance to the end) is equal to ​0​.

This function template is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when `std::counted_iterator<I>` is an associated class of the arguments.

The `!=` operator is synthesized from `operator==`.

### Parameters

x | - | an iterator adaptor

### Return value

true if x.count() is equal to ​0​, false otherwise.

### Example

Run this code

    #include <initializer_list>
    #include <iterator>

    int main()
    {
        static constexpr auto v = {1, 2, 3, 4};
        constexpr std::counted_iterator<std::initializer_list<int>::iterator>
            it1 {v.begin(), 3},
            it2 {v.begin(), 0};
        static_assert( it1 != std::default_sentinel );
        static_assert( it2 == std::default_sentinel );
        static_assert( std::default_sentinel != it1 );
        static_assert( std::default_sentinel == it2 );
    }

### See also

operator==operator<=> (C++20) | compares the distances to the end (function template)

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