{ std::unordered_map<int, std::string> myMap = {{1, "apple"}, {2, "banana"}, {3, "orange"}}; for (const auto& pair : myMap) { std::cout << "Key: " << pair.first << ", Value: " <<
std::size_toperator()(constKEY &key)const{usingstd::size_t;usingstd::hash;//Compute individual hash values for first,//second and third and combine them using XOR//and bit shifting:return((hash<int>()(key.first)^ (hash<int>()(key.second) <<1)) >>1)^ (hash<int>()(key.third...
int main() { auto hashlambda = [](const pair<int, int>& i) -> size_t{return i.first ^ i.second;}; unordered_map<pair<int, int>, int, decltype(hashlambda)> lam_map(10, hashlambda); lam_map[make_pair(1, 2)]++; return 0; } 1. 2. 3. 4. 5. 6. 我们在创建unordered_m...
cout<< ii->first.name<<""<< ii->first.age<<":"<< ii->second<<endl;return0; }
intmain(){std::unordered_map<int,std::string>c={{1,"one"},{2,"two"},{3,"three"},{4,"four"},{5,"five"},{6,"six"}};// 从 c 擦除所有奇数for(autoit=c.begin();it!=c.end();)if(it->first%2==1)it=c.erase(it);else++it;for(auto&p:c)std::cout<<p.second<<' '...
#include<iostream>#include<unordered_map>#include<string>intmain(){std::unordered_map<std::string,std::string>myMap;// 插入键值对 "key1": "value1"autoit=myMap.insert_or_assign("key1","value1");std::cout<<"Key1 inserted/updated: "<<it->second<<std::endl;// 更新键值对 "key1"...
cout << it->second.c_str() << endl; } system("pause"); return 0; } 二、关于 Lambda实现 Hash函数的说明 C++ STL中的unordered_map底层是通过Hash实现的,当使用pair作为键值(Key)时,需要手动传入Hash实例类型,转载自。 1. 函数对象的实现方式 参考网上的解决方案,通过一个函数对象向unordered_map传递...
second; std::cout << "inserting 1 -> \"another one\" " << (ok ? "succeeded" : "failed") << '\n'; std::cout << "contents:\n"; for(auto& p: dict) std::cout << " " << p.first << " => " << p.second << '\n'; } 可能的输出: inserting 1 -> "another one"...
__p3_ -> second, equal_to<std::string>,数据的比较器 2: 散列计算器,string -> hash hash<std::string>,在std::string实现。提供operator()操作符,作为计算hash数值的入口方法 1template <class_CharT,class_Allocator>2struct_LIBCPP_TEMPLATE_VIS3hash<basic_string<_CharT, char_traits<_CharT>, _Al...
it->first;// same as (*it).first (the key value)it->second;// same as (*it).second (the mapped value) Member types The following aliases are member types of unordered_map. They are widely used as parameter and return types by member functions: ...