C++ でのつまづき

[kochigami]

vector<Point2d> pre_centers;
... // pre_centers に値を代入(push_back)
                                                         
for (int i=0; i != int (pre_centers.size()); i++){                                 
      cout << i << endl;         // i が無限に増える                                                      
      pre_centers.pop_back();                                                     
     }        

[kochigami]

これはだめ
distCoeffs = Mat_<double>(1,5) << 0.081784, -0.713658, 0.028528, 0.002789, 0.000000;
正しくは
distCoeffs = (cv::Mat_<double>(1,5) << 0.081784, -0.713658, 0.028528, 0.002789, 0.000000);