[英]What is the default hash function used in C++ std::unordered_map?
[英]what hash function is being used by boost c++ unordered_map?
boost c ++ unordered_map正在使用什么哈希函數? 我的意思是boost :: hash正在使用什么樣的哈希算法
template <> struct hash;
謝謝
默認情況下,它使用boost :: hash :)
這取決於你使用的類型,如果你看這里 boost::hash
模板類是專門的:
template<> struct hash<bool>;
template<> struct hash<char>;
template<> struct hash<signed char>;
template<> struct hash<unsigned char>;
template<> struct hash<wchar_t>;
template<> struct hash<short>;
template<> struct hash<unsigned short>;
template<> struct hash<int>;
template<> struct hash<unsigned int>;
template<> struct hash<long>;
template<> struct hash<unsigned long>;
template<> struct hash<long long>;
template<> struct hash<unsigned long long>;
template<> struct hash<float>;
template<> struct hash<double>;
template<> struct hash<long double>;
template<> struct hash<std::string>;
template<> struct hash<std::wstring>;
template<typename T> struct hash<T*>;
您還可以將自己的哈希指定為第三個模板參數:
namespace boost {
template<typename Key, typename Mapped, typename Hash = boost::hash<Key>,
typename Pred = std::equal_to<Key>,
typename Alloc = std::allocator<std::pair<Key const, Mapped> > >
class unordered_map;
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.