std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>::value_comp
From cppreference.com
| std::flat_map::value_compare value_comp() const; |
(since C++23) | |
Returns a function object that compares objects of type std::flat_map::value_type (key-value pairs) by using key_comp to compare the first components of the pairs.
Parameters
(none)
Return value
The value comparison function object.
Complexity
Constant.
Example
Run this code
#include <iostream> #include <flat_map> #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_map<int, char, ModCmp> cont; cont = {{1, 'a'}, {2, 'b'}, {3, 'c'}, {4, 'd'}, {5, 'e'}}; auto comp_func = cont.value_comp(); for (const std::pair<int, char> val = {100, 'a'}; auto it : cont) { const bool before = comp_func(it, val); const bool after = comp_func(val, it); std::cout << '(' << it.first << ',' << it.second << ") "; if (!before && !after) std::cout << "equivalent to key (" << val.first << ")\n"; else if (before) std::cout << "goes before key (" << val.first << ")\n"; else if (after) std::cout << "goes after key (" << val.first << ")\n"; else std::unreachable(); } }
Output:
(1,a) goes before key (100) (2,b) goes before key (100) (3,c) equivalent to key (100) (4,d) goes after key (100) (5,e) goes after key (100)
See also
| returns the function that compares keys (public member function) |