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std::flat_m...:value_comp(3)  C++ Standard Libary std::flat_m...:value_comp(3)

NAME
       std::flat_multiset::value_comp -	std::flat_multiset::value_comp

Synopsis
	  std::flat_multiset::value_compare value_comp() const;	 (since	C++23)

	  Returns the function object that compares the	values.	It is the same
       as key_comp.

Parameters
	  (none)

Return value
	  The value comparison function	object.

Complexity
	  Constant.

Example
       // Run this code

	#include <iostream>
	#include <flat_set>
	#include <utility>

	// Example module 97 key compare function
	struct ModCmp
	{
	    bool operator()(int	lhs, int rhs) const
	    {
		return (lhs % 97) < (rhs % 97);
	    }
	};

	int main()
	{
	    std::flat_multiset<int, ModCmp> cont{1, 2, 3, 4, 5};

	    // Same behaviour as key_comp()
	    auto comp_func = cont.value_comp();

	    for	(const int val{100}; const int key : cont)
	    {
		const bool before = comp_func(key, val);
		const bool after = comp_func(val, key);

		std::cout << "Key (" <<	key << ") ";
		if (!before && !after)
		    std::cout << "equivalent to	key (" << val << ")\n";
		else if	(before)
		    std::cout << "goes before key (" <<	val << ")\n";
		else if	(after)
		    std::cout << "goes after key (" << val << ")\n";
		else
		    std::unreachable();
	    }
	}

Output:
	Key (1)	goes before key	(100)
	Key (2)	goes before key	(100)
	Key (3)	equivalent to key (100)
	Key (4)	goes after key (100)
	Key (5)	goes after key (100)

See also
	  key_comp returns the function	that compares keys
		   (public member function)

http://cppreference.com		  2024.06.10	  std::flat_m...:value_comp(3)

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