【C++ Primer | 11】关联容器（一）
在multimap或multiset中查找元素
第二种方法解释：
1 #include <iostream> 2 #include <utility> 3 #include <iterator> 4 #include <functional> 5 #include <algorithm> 6 #include <map> 7 #include <set> 8 #include <string> 9 using namespace std; 10 11 int main() 12 { 13 pair<string, int> p[] = { {"a", 1}, 14 {"c", 3}, 15 {"b", 2}, 16 {"d", 4}, 17 {"a", 6}, 18 {"a", 9} }; 19 multimap<string, int> mm(begin(p), end(p)); 20 for (auto q : mm) 21 { 22 cout << q.first << " " << q.second << endl; 23 } 24 //第一种方法 find+count 25 string search_item("a"); 26 auto entries = mm.count(search_item); 27 auto iter = mm.find(search_item); 28 while (entries) 29 { 30 cout << iter->second << endl; 31 ++iter; 32 --entries; 33 } 34 //第二种方法：面向迭代器的解决方法 35 for (auto beg = mm.lower_bound(search_item), end = mm.upper_bound(search_item); beg != end; ++beg) 36 { 37 cout << beg->second << " "; 38 } 39 //第二种方法：利用equal_range函数 40 for (auto pos = mm.equal_range(search_item); pos.first != pos.second; ++pos.first) 41 { 42 cout << pos.first->second << " "; 43 } 44 system("pause"); 45 return 0; 46 }
输出结果：
