c++关联容器的成员函数find的一个例子

 先来一个灰色难懂的部分镇楼。

#include <string>
#include <iostream>
#include <list>
#include <vector>
#include <set>
#include <map>
#include <utility>
#include <algorithm>
using namespace std;
int main()
{
set<int> iset = {0,1,2,3,4,5,6,7,8,9};
set<int>::iterator pos1 = iset.find(1);
cout << *pos1 << endl;
auto pos2 = iset.find(11);
if(pos2 == iset.end())
        cout<< "yes" << endl;
auto n = iset.count(1);
cout << n << endl;
auto n1 = iset.count(11);
cout << n1 << endl;
        
multimap<string,size_t> m1{
  {"abc",1},{"abc",2},{"abcd",3}};
auto pos3 = m1.find("abc");
if(pos3 == m1.end()