<unordered_map> functions <unordered_map> operators unordered_map class unordered_multimap class <unordered_set> <utility> <valarray> <variant> <vector> C++ Standard Library overview C++ Standard Library contai
unordered_map 是一个关联容器,它存储由键值和映射值组合形成的元素。键值用于唯一标识元素,映射的值是与键关联的内容。键和值都可以是预定义或用户定义的任何类型。 内部unordered_map 是使用Hash Table实现的,提供给 map 的键被散列到散列表的索引中,这就是为什么数据结构的性能很大程度上取决于散列函数,但平均而...
In an unordered map of C++, a plethora of functions is present. The most useful among them are = operator, [] operator, iterator begin and end, size and empty for capacity, lookup find and count, modification- insert and erase. How unordered_map function work in C++? In unordered_map, ...
member functions: unordered_map::at unordered_map::begin unordered_map::bucket unordered_map::bucket_count unordered_map::bucket_size unordered_map::cbegin unordered_map::cend unordered_map::clear unordered_map::count unordered_map::emplace unordered_map::emplace_hint unordered_map::empty unordered...
Notice that anunordered_mapobject makes no guarantees on which order its elements follow. But, in any case, the range that goes from itsbeginto itsendcovers all the elements in the container (or the bucket), until invalidated. Parameters ...
Functions from <unordered_map> Below is list of all methods from <unordered_map> header. Constructors Sr.No.Method & Description 1 unordered_map::unordered_map default constructor Constructs an empty unordered_map with zero elements. 2 unordered_map::unordered_map copy constructor Constructs an un...
<unordered_map> std::unordered_map::max_size size_type max_size() const noexcept; Return maximum size Returns the maximum number of elements that theunordered_mapcontainer can hold. This is the maximum potential number of elements the container can hold due to system constraints or limitations ...
unordered_map::clear unordered_map::const_iterator unordered_map::const_local_iterator unordered_map::const_pointer unordered_map::const_reference unordered_map::count unordered_map::difference_type unordered_map::empty unordered_map::end unordered_map::equal_range ...
void foo(const std::unordered_map<int,int> &) {} int main() { foo({}); } GCC版本大于或者等于4.9,会报如下错误 1 map2.cpp:7:19: error: converting to ‘const std::unordered_map<int, int>’ from initializer list would use explicit constructor ‘std::unordered_map<_Key, _Tp, _Has...
unordered_set, unordered_multiset, unordered_map, unordered_multimap的底层实现皆为_Hashtable,定义于bits/hashtable.h。 以unordered_set 为例,它内含了一个指定了模板参数的_Hashtable。 //unordered_set.h37/// Base types for unordered_set.38template<bool_Cache>39using__uset_traits=__detail::_Hash...