vector中pair的“>>”写法

#include <iostream>#include <vector>using namespace std;int main(){    vector< pair<int, int> > pvec;   //如果写成vector<pair<int, int>> pvec;编译器会误认为流运算    pair<int,int> par;    par.first = 9;    par.second = 23;    pvec.push_back(par);    pair<int, int> par2 = *pvec.begin();    cout << par2.second << endl;    return 0;}