operator==,<=>(std::inplace_vector)

 

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inplace_vector (C++26)

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std::inplace_vector

Member types
Member functions
inplace_vector::inplace_vector inplace_vector::~inplace_vector    inplace_vector::operator= inplace_vector::assign inplace_vector::assign_range Size and capacity inplace_vector::empty inplace_vector::size inplace_vector::max_size inplace_vector::capacity inplace_vector::resize inplace_vector::reserve inplace_vector::shrink_to_fit Iterators inplace_vector::begininplace_vector::cbegin inplace_vector::endinplace_vector::cend inplace_vector::rbegininplace_vector::crbegin inplace_vector::rendinplace_vector::crend	Element access inplace_vector::at inplace_vector::operator[] inplace_vector::front inplace_vector::back inplace_vector::data Modifiers inplace_vector::clear inplace_vector::erase inplace_vector::swap inplace_vector::insert inplace_vector::insert_range inplace_vector::emplace inplace_vector::emplace_back inplace_vector::try_emplace_back inplace_vector::unchecked_emplace_back inplace_vector::push_back inplace_vector::try_push_back inplace_vector::unchecked_push_back inplace_vector::pop_back inplace_vector::append_range inplace_vector::try_append_range
Non-member functions
erase(std::inplace_vector)erase_if(std::inplace_vector) swap(std::inplace_vector)	operator==operator<=>

 

constexpr friend bool operator==( const std::inplace_vector<T, N>& lhs,                                   const std::inplace_vector<T, N>& rhs );	(1)	(since C++26)
constexpr friend synth-three-way-result<T>     operator<=>( const std::inplace_vector<T, N>& lhs,                  const std::inplace_vector<T, N>& rhs );	(2)	(since C++26)

Compares the contents of two std::inplace_vectors.

1) Checks if the contents of lhs and rhs are equal, that is, they have the same number of elements and each element in lhs compares equal with the element in rhs at the same position.

2) Compares the contents of lhs and rhs lexicographically. The comparison is performed as if by calling
std::lexicographical_compare_three_way(lhs.begin(), lhs.end(),
                                       rhs.begin(), rhs.end(), synth-three-way);.

The return type is the return type of synth-three-way (i.e., synth-three-way-result <T>).

At least one of the following conditions must be satisfied:

• T models three_way_comparable.
• < is defined for values of type (possibly const-qualified) T, and < is a total ordering relationship.

   Otherwise, the behavior is undefined.

The <, <=, >, >=, and != operators are synthesized from operator<=> and operator== respectively.

Parameters

lhs, rhs	-	std::inplace_vectors whose contents to compare
- T must meet the requirements of EqualityComparable in order to use overloads (1).

Return value

1) true if the contents of the std::inplace_vectors are equal, false otherwise.

2) The relative order of the first pair of non-equivalent elements in lhs and rhs if there are such elements, lhs.size() <=> rhs.size() otherwise.

Complexity

1) Constant if lhs and rhs are of different size, otherwise linear in the size of the std::inplace_vector.

2) Linear in the size of the std::inplace_vector.

Notes

The relational operators are defined in terms of synth-three-way, which uses operator<=> if possible, or operator< otherwise.

Notably, if the element does not itself provide operator<=>, but is implicitly convertible to a three-way comparable type, that conversion will be used instead of operator<.

Example

Run this code

#include <inplace_vector>
 
int main()
{
    constexpr std::inplace_vector<int, 4>
        a{1, 2, 3},
        b{1, 2, 3},
        c{7, 8, 9, 10};
 
    static_assert
    (""
        "Compare equal containers:" &&
        (a != b) == false &&
        (a == b) == true &&
        (a < b) == false &&
        (a <= b) == true &&
        (a > b) == false &&
        (a >= b) == true &&
        (a <=> b) >= 0 &&
        (a <=> b) <= 0 &&
        (a <=> b) == 0 &&
 
        "Compare non equal containers:" &&
        (a != c) == true &&
        (a == c) == false &&
        (a < c) == true &&
        (a <= c) == true &&
        (a > c) == false &&
        (a >= c) == false &&
        (a <=> c) < 0 &&
        (a <=> c) != 0 &&
        (a <=> c) <= 0 &&
    "");
}