std::map满足容器(Container)、知分配器容器(AllocatorAwareContainer)、关联容器(AssociativeContainer)和可逆容器(ReversibleContainer)。 std::map的全部成员函数均为constexpr:在常量表达式求值中创建并使用std::map对象是可能的。 然而,std::map对象通常不能为constexpr,因为任何动态分配的存储都必须在相同的常量表达式...
#include <iostream> #include <map> void println(auto rem, auto const& container) { std::cout << rem << '{'; for (char sep[]{0, ' ', 0}; const auto& [key, value] : container) std::cout << sep << '{' << key << ", " << value << '}', *sep = ','; std::cou...
>usingmap=std::map<Key, T, Compare, std::pmr::polymorphic_allocator<std::pair<constKey, T>>>; } (2)(since C++17) std::mapis a sorted associative container that contains key-value pairs with unique keys. Keys are sorted by using the comparison functionCompare. Search, removal, and in...
有提示插入(4-6)不返回布尔值,这是为了与顺序容器上的定位插入,如std::vector::insert签名兼容。这使得可以创建泛型插入器,例如std::inserter。检查有提示插入是否成功的一种方式是比较插入前后的size()。 示例 运行此代码 #include <iomanip>#include <iostream>#include <map>#include <string>usingnamespacestd...
External Links−Non-ANSI/ISO Libraries−Index−std Symbol Index C reference C89,C95,C99,C11,C17,C23│Compiler supportC99,C23 Language Basic concepts Keywords Preprocessor Expressions Declaration Initialization Functions Statements Headers Type support ...
basic_string_view (C++17) Chaînes terminées par null: byte − multibyte − wide Conteneurs array (C++11) − vector map − unordered_map (C++11) priority_queue − span (C++20) Autres conteneurs: sequence − associative unordered associative − adaptors Itérate...
L'utilisation de ce paramètre comme un modèle pour std::unordered_map, std::unordered_set, etc exige également la spécialisation des std::equal_to . Original: Demonstrates creation of a hash function for a user defined type. Using this as a template parameter for std::unordered_map, ...
; std::hash<std::string> hash_fn; size_t str_hash = hash_fn(str); std::cout << str_hash << '\n'; } Output: 391070135 Veranschaulicht Schaffung einer Hash-Funktion für einen Benutzer definierten Typ. Mit diesem als Template-Parameter für std::unordered_map, std::unordered_set...
std::map::at Parameters k Key value of the element whose mapped value is accessed. Member type key_type is the type of the keys for the elements in the container, defined in map as an alias of its first template p...using namespace std; using namespace std; using namespace std;...
#include <iostream> #include <map> #include <utility> // Example module 97 key compare function struct ModCmp { bool operator()(int lhs, int rhs) const { return (lhs % 97) < (rhs % 97); } }; int main() { std::map<int, char, ModCmp> cont; cont = {{1, 'a'}, {2, ...