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

From cppreference.com
< cpp‎ | iterator‎ | move iterator

| (1) |
template< class Iterator1, class Iterator2 > bool operator==( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator==( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17)
| (2) |
template< class Iterator1, class Iterator2 > bool operator!=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator!=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17) (until C++20)
| (3) |
template< class Iterator1, class Iterator2 > bool operator<( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator<( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17)
| (4) |
template< class Iterator1, class Iterator2 > bool operator<=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator<=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17)
| (5) |
template< class Iterator1, class Iterator2 > bool operator>( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator>( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17)
| (6) |
template< class Iterator1, class Iterator2 > bool operator>=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (until C++17)
template< class Iterator1, class Iterator2 > constexpr bool operator>=( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); |  | (since C++17)
template< class Iterator1, std::three_way_comparable_with<Iterator1> Iterator2 > constexpr std::compare_three_way_result_t<Iterator1, Iterator2> operator<=>( const std::move_iterator<Iterator1>& lhs, const std::move_iterator<Iterator2>& rhs ); | (7) | (since C++20)

Compares the underlying iterators.

(1-6) only participate in overload resolution if their underlying comparison expressions (see below) are 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 <compare>
    #include <iostream>
    #include <iterator>

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

        std::move_iterator<int*>
            x {std::end(a) - 1},
            y {std::end(a) - 1},
            z {std::end(a) - 2};

        std::cout
            << std::boolalpha
            << "*x == " << *x << '\n' // 6
            << "*y == " << *y << '\n' // 6
            << "*z == " << *z << '\n' // 7
            << "x == y ? " << (x == y) << '\n' // true
            << "x != y ? " << (x != y) << '\n' // false
            << "x <  y ? " << (x <  y) << '\n' // false
            << "x <= y ? " << (x <= y) << '\n' // true
            << "x == z ? " << (x == z) << '\n' // false
            << "x != z ? " << (x != z) << '\n' // true
            << "x <  z ? " << (x <  z) << '\n' // false
            << "x <= z ? " << (x <= z) << '\n' // false
            << "x <=> y == 0 ? " << (x <=> y == 0) << '\n' // true
            << "x <=> y <  0 ? " << (x <=> y <  0) << '\n' // false
            << "x <=> y >  0 ? " << (x <=> y >  0) << '\n' // false
            << "x <=> z == 0 ? " << (x <=> z == 0) << '\n' // false
            << "x <=> z <  0 ? " << (x <=> z <  0) << '\n' // true
            << "x <=> z >  0 ? " << (x <=> z >  0) << '\n' // false
            ;
    }

Output:

    *x == 6
    *y == 6
    *z == 7
    x == y ? true
    x != y ? false
    x <  y ? false
    x <= y ? true
    x == z ? false
    x != z ? true
    x <  z ? false
    x <= z ? false
    x <=> y == 0 ? true
    x <=> y <  0 ? false
    x <=> y >  0 ? false
    x <=> z == 0 ? false
    x <=> z <  0 ? false
    x <=> z >  0 ? true

### See also

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

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