Mastering stdunordered_map in C++ A Practical Guide

Unordered Map Emplace. 算法作业1：倒水问题——三壶谜题 The constructor of the element type (value_type, that is, std:: pair < const Key, T >) is called with exactly the same arguments as supplied to the function, forwarded with std:: forward < Args > (args)..If rehashing occurs due to the insertion, all iterators are. The argument(s) for the key that you pass to emplace() are directly forwarded to a Foo constructor call within unordered_map::emplace()'s definition (optional additional details: where this newly constructed object is immediately incorporated into one of unordered_map's member variables so that no destructor is called when execution leaves emplace() and no move or copy constructors are called).

The constructor of the element type (value_type, that is, std:: pair < const Key, T >) is called with exactly the same arguments as supplied to the function, forwarded with std:: forward < Args > (args)..If rehashing occurs due to the insertion, all iterators are. All member functions of std::unordered_map are constexpr: it is possible to create and use std::unordered_map objects in the evaluation of a constant expression.

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unordered_map<.>::emplace() method C++ documentation The argument(s) for the key that you pass to emplace() are directly forwarded to a Foo constructor call within unordered_map::emplace()'s definition (optional additional details: where this newly constructed object is immediately incorporated into one of unordered_map's member variables so that no destructor is called when execution leaves emplace() and no move or copy constructors are called). If inserted, this effectively increases the container size by one.

stdunordered_map Interface Sheet hacking C++. Inserts a new element into the container constructed in-place with the given args if there is no element with the key in the container. All member functions of std::unordered_map are constexpr: it is possible to create and use std::unordered_map objects in the evaluation of a constant expression.

Mastering stdunordered_map in C++ A Practical Guide. It effectively increases the container size by one The unordered_map::emplace() is a built-in function in C++ STL which inserts the key and its element in the unordered_map container