ReferenceC library: <cassert> (assert.h) <cctype> (ctype.h) <cerrno> (errno.h) <cfenv> (fenv.h) <cfloat> (float.h) <cinttypes> (inttypes.h) <ciso646> (iso646.h) <climits> (limits.h) <clocale> (locale.h) <cmath> (math.h) <csetjmp> (setjmp.h) <csignal> (signal.h...
( unordered_multimap<K, T, H, P, A>& c, Predicate pred); namespace pmr { template<class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>> using unordered_map = std::unordered_map<Key, T, Hash, Pred, polymorphic_allocator<pair<const Key, T>>>; template<...
示例程序:(摘自cppreference.com) #include <unordered_map> #include <iostream> int main() { 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(auto it = c.begin()...
const_referenceconst value_type& pointerstd::allocator_traits<Allocator>::pointer const_pointerstd::allocator_traits<Allocator>::const_pointer iterator遗留向前迭代器(LegacyForwardIterator) const_iterator常向前迭代器 local_iterator类别、值、差、指针和引用类型都与iterator相同的迭代器类型。
Erases all elements that satisfy the predicatepredfromc. Equivalent to autoold_size=c.size();for(autofirst=c.begin(), last=c.end();first!=last;){if(pred(*first))first=c.erase(first);else++first;}returnold_size-c.size(); Parameters ...
// unordered_map::find #include <iostream> #include <string> #include <unordered_map> int main () { std::unordered_map<std::string,double> mymap = { {'a',1}, {'b',2}, {'c',3} }; std::unordered_map<std::string,double>::const_iterator got = mymap.find('a'); if ( go...
无意中发现std::unordered_map、std::map等插入key-value对在C++17后竟有了insert()、operator[]、emplace()、try_emplace()和insert_or_assign()等超过5种方法,我们可以根据实际场景和对效率的要求,去选择不同的方法。在此不得不夸一夸C++的灵(fù)活(zá)性,不管怎么说,一点无用的知识又增加了。此外发现...
{std::unordered_map<int,char>cont{{1,'a'},{2,'b'},{3,'c'}};print("Start:", cont);// Extract node handle and change keyautonh=cont.extract(1);nh.key()=4;print("After extract and before insert:", cont);// Insert node handle backcont.insert(std::move(nh));print("End:"...
#include <cmath> #include <iostream> #include <unordered_map>struct Node { double x, y; };int main() { Node nodes[3] = {{1, 0}, {2, 0}, {3, 0}};// mag 是映射 Node 地址到其平面中长度的 map std::unordered_map<Node...
unordered_map容器,直译过来就是"无序map容器"的意思。所谓“无序”,指的是unordered_map容器不会像map容器那样对存储的数据进行排序。换句话说,unordered_map容器和map容器仅有一点不同,即map容器中存储的数据是有序的,而unordered_map容器中是无序的。头文件。