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 #...
std::vector<T,Allocator>::emplace_back From cppreference.com <cpp |container |vector std::vector Member types Member functions vector::vector vector::~vector vector::operator= vector::assign vector::assign_range (C++23) vector::get_allocator ...
push_back、emplace_backvector 更改容量时全部失效。否则只有end()。 insert、emplacevector 更改容量时全部失效。否则只有在或于插入点后者(包括end())。 resizevector 更改容量时全部失效。否则只有end()与被擦除元素。 pop_back被擦除元素和end()。
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(...
#include <inplace_vector> #include <new> #include <print> #include <string> #include <utility> int main() { std::inplace_vector<std::pair<std::string, std::string>, 2> fauna; std::string dog{"\N{DOG}"}; fauna.unchecked_emplace_back("\N{CAT}", dog); fauna.unchecked_emplace_...
inplace_vector(C++26) hive(C++26) map−multimap−set−multiset unordered_map(C++11) unordered_multimap(C++11) unordered_set(C++11) unordered_multiset(C++11) Container adaptors span(C++20)−mdspan(C++23) Iterators library Ranges library(C++20) ...
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...
类模板 std::vectornamespace std { template<class T, class Allocator = allocator<T>> class vector { public: // 类型 using value_type = T; using allocator_type = Allocator; using pointer = typename allocator_traits<Allocator>::pointer; using const_pointer = typename allocator_traits<Allocator...
- T 必须为从 *ranges::begin(rg) 可就位构造 (EmplaceConstructible) 到vector。且,T 必须可移动插入 (MoveInsertable) 到vector。否则,行为未定义。 复杂度如果发生重分配,则与结果 vector 的元素数量呈线性;否则,与所插入元素数量加上到 end() 的距离呈线性。 异常...
vector::insert vector::emplace (C++11) vector::erase vector::push_back vector::emplace_back (C++11) vector::pop_back vector::resize vector::swap std::vector<bool> specific vector<bool>::flip vector<bool>::swap Non-member functions operator==operator!=operator<operator>operator<=operator>=...