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operator==,!=(std::match_results)

Defined in header <regex> 
template< class BidirIt, class Alloc >
bool operator==( match_results<BidirIt,Alloc>& lhs,
                 match_results<BidirIt,Alloc>& rhs );
 (1) (since C++11) 
template< class BidirIt, class Alloc >
bool operator!=( match_results<BidirIt,Alloc>& lhs,
                 match_results<BidirIt,Alloc>& rhs );
 (2) (since C++11)
(until C++20)

Compares two match_results objects.

Two match_results are equal if the following conditions are met:

  • neither of the objects is ready, or
  • both match results are ready and the following conditions are met:
  • lhs.empty() and rhs.empty(), or
  • !lhs.empty() and !rhs.empty() and the following conditions are met:
    • lhs.prefix() == rhs.prefix()
    • lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin())
    • lhs.suffix() == rhs.suffix()
1) Checks if lhs and rhs are equal.
2) Checks if lhs and rhs are not equal.

The != operator is synthesized from operator==.

 (since C++20)

Parameters

lhs, rhs - match results to compare
Type requirements
-BidirIt must meet the requirements of LegacyBidirectionalIterator.
-Alloc must meet the requirements of Allocator.

Return value

1) true if lhs and rhs are equal, false otherwise.
2) true if lhs and rhs are not equal, false otherwise.

Exceptions

May throw implementation-defined exceptions.

Example

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https://en.cppreference.com/w/cpp/regex/match_results/operator_cmp