# operator==,!=,<,<=,>,>=,<=>(std::move_iterator)

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< cpp‎ | iterator‎ | move iterator

Defined in header `<iterator>` |  |
template< class Iter1, class Iter2 > bool operator==( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (1) | (constexpr since C++17)
template< class Iter1, class Iter2 > bool operator!=( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (2) | (constexpr since C++17) (until C++20)
template< class Iter1, class Iter2 > bool operator< ( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (3) | (constexpr since C++17)
template< class Iter1, class Iter2 > bool operator<=( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (4) | (constexpr since C++17)
template< class Iter1, class Iter2 > bool operator> ( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (5) | (constexpr since C++17)
template< class Iter1, class Iter2 > bool operator>=( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (6) | (constexpr since C++17)
template< class Iter1, std::three_way_comparable_with <Iter1> Iter2 > constexpr std::compare_three_way_result_t <Iter1, Iter2> operator<=>( const std::move_iterator <Iter1>& lhs, const std::move_iterator <Iter2>& rhs ); | (7) | (since C++20)

Compares the underlying iterators of lhs and rhs.

1) This overload participates in overload resolution only if lhs.base() == rhs.base() is well-formed and convertible to bool. 3-6) These overloads participate in overload resolution only if lhs.base() < rhs.base() is well-formed and convertible to bool. The `!=` operator is synthesized from `operator==`. | (since C++20)

### Parameters

lhs, rhs | - | iterator adaptors to compare

### Return value

1) lhs.base() == rhs.base()
2) !(lhs == rhs)
3) lhs.base() < rhs.base()
4) !(rhs < lhs)
5) rhs < lhs
6) !(lhs < rhs)
7) lhs.base() <=> rhs.base()

### Example

Run this code

    #include <cassert>
    #include <iterator>

    int main()
    {
        int a[]{9, 8, 7, 6};
        //            │  └───── x, y
        //            └──────── z

        // “x” and “y” are equal, but “x” is greater than “z”
        std::move_iterator<int*>
            x{std::end(a) - 1},
            y{std::end(a) - 1},
            z{std::end(a) - 2};

        // two-way comparisons
        assert(  x == y );
        assert(!(x != y));
        assert(!(x <  y));
        assert(  x <= y );
        assert(!(x == z));
        assert(  x != z );
        assert(!(x <  z));
        assert(!(x <= z));

        // three-way comparisons
        assert(  x <=> y == 0 );
        assert(!(x <=> y <  0));
        assert(!(x <=> y >  0));
        assert(!(x <=> z == 0));
        assert(!(x <=> z <  0));
        assert(  x <=> z >  0 );
    }

### See also

operator==(std::move_sentinel) (C++20) | compares the underlying iterator and the underlying sentinel (function template)

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