c++ map的equal_range函数，寻找multimap中key等于某个关键字(c++primer 5th，11.3.5习题答案)

#include <vector>
#include <set>
#include <map>
using namespace std;
int main()
{
multimap<string,int> m{
  
  {"str1",1},{"str2",23},{"str2",234},{"str2",234},{"str2",123},{"str2",154},{"str2",34},{"str3",75}};

//equal_range()函数的返回值是pair，类型是指向原来的map对象的迭代器，所以定义equal_range
//返回类型如下：

pair<map<string,int>::iterator,map<string,int>::iterator> iters = m.equal_range("str2");
multimap<string,int>::iterator it,beg = iters.first;
multimap<string,int>::iterator end = iters.second;
for(it = beg;it != end;++it)
  {
  cout << it -> second << endl;
  }

        return 0;
}
~  

或者可以按照下面的方法写：

#include <string>
#include <iostream>
#include <list>
#include <vector>