std::flat_multimap<Key,T,Compare,KeyContainer,MappedContainer>::key_comp
来自 cppreference.com
| key_compare key_comp() const; |
(自 C++23 起) | |
返回比较键的函数对象，它是此容器的 构造函数 参数 comp 的副本。
内容 |
[编辑] 参数
(无)
[编辑] 返回值
键比较函数对象。
[编辑] 复杂度
常数。
[编辑] 示例
运行此代码
#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_multimap<int, char, ModCmp> cont; cont = {{1, 'a'}, {2, 'b'}, {3, 'c'}, {4, 'd'}, {5, 'e'}}; auto comp_func = cont.key_comp(); for (const auto it : cont) { const bool before = comp_func(it.first, 100); const bool after = comp_func(100, it.first); std::cout << "Key (" << it.first << ',' << it.second << ") "; 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(); } }
输出
(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)
[编辑] 另请参阅
返回比较类型为 value_type 的对象的键的函数(公有成员函数) |
