unordered_map<int,char>example{{1,'a'},{2,'b'}};if(autosearch=example.find(2);search!=example.end())std::cout<<"Found "<<search->first<<' '<<search->second<<'\n';elsestd::cout<<"Not found\n";// C++20 demo: Heterogeneous lookup for unordered containers (transparent hashing)...
unordered_map::operator[] unordered_map::count unordered_map::find unordered_map::contains (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) unordered_map::end(size_type)unordered_map::cend(size_type) ...
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) Range factories−Range adaptors generator(C++23) Algorithms library ...
unordered_multimap 创建账户 std::unordered_multimap 在标头<unordered_map>定义 template< classKey, classT, classHash=std::hash<Key>, classKeyEqual=std::equal_to<Key>, classAllocator=std::allocator<std::pair<constKey, T>> >classunordered_multimap;...
#include <iostream>#include <string>#include <unordered_map>intmain(){std::unordered_map<int,std::string>dict={{1,"one"},{2,"two"}};dict.insert({3,"three"});dict.insert(std::make_pair(4,"four"));dict.insert({{4,"another four"},{5,"five"}});constboolok=dict.insert({1,...
std::multimap<int,std::string>a={{3,"BMW"},{1,"Cruze"},{2,"City"},{1,"Sail"}};autob=a.equal_range(2);for(autox=std::make_reverse_iterator(b.second);x!=a.rend();++x){std::cout<<x->first<<" --> "<<x->second<<std::endl;}return0;} ...
unordered_map::operator[] unordered_map::count unordered_map::find unordered_map::contains (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) unordered_map::end(size_type)unordered_map::cend(size_type) ...
>usingunordered_map= std::unordered_map<Key, T, Hash, KeyEqual, std::pmr::polymorphic_allocator<std::pair<constKey, T>>>; } (2)(since C++17) std::unordered_mapis an associative container that contains key-value pairs with unique keys. Search, insertion, and removal of elements have ...
#include <iostream>#include <unordered_map>intmain(){std::unordered_map<int,char>example{{1,'a'},{2,'b'}};for(intx:{2,5})if(example.contains(x))std::cout<<x<<": 找到\n";elsestd::cout<<x<<": 未找到\n";} 输出:
;// mag 是映射 Node 地址到其平面中长度的 map std::unordered_map<Node*, double> mag = { { nodes + 0, 1 }, { nodes + 1, 2 }, { nodes + 2, 3 } };// 从 0 到长度更改每个 y 坐标 for (auto iter = mag.begin(); iter ...