Namespaces
Variants
Actions

std::flat_set<Key,Compare,KeyContainer>::key_comp

From cppreference.com
< cpp‎ | container‎ | flat set
 
 
 
std::flat_set
 
key_compare key_comp() const;
(since C++23)
(constexpr since C++26)

Returns the function object that compares the keys, which is a copy of the key comparison object used by *this.It is the same as value_comp().

[edit] Return value

The key comparison function object.

[edit] Complexity

Constant.

[edit] 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_set <int, ModCmp> cont{1, 2, 3, 4, 5};
 
 auto comp_func = cont.key_comp();
 
 for (const int key : cont)
 {
 const bool before = comp_func(key, 100);
 const bool after = comp_func(100, key);
 
 std::cout << '(' << key << ") ";
 if (!before && !after)
 std::cout << "equivalent to key (100)\n";
 else if (before)
 std::cout << "goes before key (100)\n";
 else if (after)
 std::cout << "goes after key (100)\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)

[edit] See also

returns the function that compares keys in objects of type value_type
(public member function) [edit]
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/flat_set/key_comp&oldid=169250"

AltStyle によって変換されたページ (->オリジナル) /