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std::multimap::emplace(3) C++ Standard Libary std::multimap::emplace(3) NAME std::multimap::emplace - std::multimap::emplace Synopsis template< class... Args > (since C++11) iterator emplace( Args&&... args ); Inserts a new element into the container constructed in-place with the given args . Careful use of emplace allows the new element to be constructed while avoiding unnecessary copy or move operations. The constructor of the new ele- ment (i.e. std::pair<const Key, T>) is called with exactly the same arguments as supplied to emplace, forwarded via std::forward<Args>(args).... No iterators or references are invalidated. Parameters args - arguments to forward to the constructor of the element Return value Returns an iterator to the inserted element. Exceptions If an exception is thrown by any operation, this function has no ef- fect (strong exception guarantee). Complexity Logarithmic in the size of the container. Example // Run this code #include <iostream> #include <utility> #include <string> #include <map> int main() { std::multimap<std::string, std::string> m; // uses pair's move constructor m.emplace(std::make_pair(std::string("a"), std::string("a"))); // uses pair's converting move constructor m.emplace(std::make_pair("b", "abcd")); // uses pair's template constructor m.emplace("d", "ddd"); // uses pair's piecewise constructor m.emplace(std::piecewise_construct, std::forward_as_tuple("c"), std::forward_as_tuple(10, 'c')); for (const auto &p : m) { std::cout << p.first << " => " << p.second << '\n'; } } Output: a => a b => abcd c => cccccccccc d => ddd See also emplace_hint constructs elements in-place using a hint (C++11) (public member function) inserts elements insert or nodes (since C++17) (public member function) http://cppreference.com 2022.07.31 std::multimap::emplace(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Complexity | Example | Output: | See also
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