因为可能发生再分配,emplace_back 对vector 要求元素类型为可移动插入 (MoveInsertable) 。 示例下列代码用 emplace_back 追加President 类型的对象到 std::vector。它演示 emplace_back 如何转发参数给 President 的构造函数,并展示如何用 emplace_back 避免用 push_back 时的额外复制或移动操作。 运行此代码 #...
deque::push_back deque::emplace_back (C++11) deque::append_range (C++23) deque::pop_back deque::resize deque::swap Non-member functions operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) ...
cout<<"emplace_back:\n";auto&ref=elections.emplace_back("Nelson Mandela","South Africa",1994);assert(ref.year==1994&&"uses a reference to the created object (C++17)");std::list<President>reElections;std::cout<<"\npush_back:\n";reElections.push_back(President("Franklin Delano Roosevelt...
template< class... Args > reference emplace_back( Args&&... args ); (C++17 起) 添加新元素到容器尾。元素通过 std::allocator_traits::construct 构造,通常用布置 new 于容器所提供的位置原位构造元素。实参 args... 以std::forward<Args>(args)... 转发到构造函数。
push_back,emplace_backIf the vector changed capacity, all of them. If not, onlyend(). insert,emplaceIf the vector changed capacity, all of them. If not, only those at or after the insertion point (includingend()). resizeIf the vector changed capacity, all of them. If not, onlyend(...
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问std::memory_order_relaxed示例在cppreference.com中EN在 C++ 编程中，有时候我们需要在不进行拷贝的...
emplace_back (C++11) baut Elemente-Platz am Ende Original: constructs elements in-place at the end The text has been machine-translated viaGoogle Translate. You can help to correct and verify the translation. Clickherefor instructions.
push_back ajoute des éléments à la fin Original: adds elements to the end The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique) [edit] emplace_back (C++11) construit des ...
{usingnamespacestd::complex_literals;usingC=std::complex<double>;usingI=std::inplace_vector<C,3>;autov=I{1.0+2.0i,3.0+4.0i};C*c=v.try_emplace_back(5.0,6.0);assert(*c==5.0+6.0i);assert((v==I{1.0+2.0i,3.0+4.0i,5.0+6.0i}));c=v.try_emplace_back(7.0,8.0);// no space =...