C++——Vector

 #include "opencv2/objdetect.hpp"
 #include "opencv2/videoio.hpp"
 #include "opencv2/highgui.hpp"
 #include "opencv2/imgproc.hpp"
 #include <iostream>
 #include <stdio.h>
 #include <stdlib.h>
 #include <conio.h>
 using namespace std;
 using namespace cv;
 int main()
 {
     std::vector<int> vec;
     vec.push_back();
     vec.push_back();
     vec.push_back();
     vec.push_back();
     cout<<vec[]<<endl;
     vector<int>::iterator it;
     for(it=vec.begin();it!=vec.end();it++){
             cout<<"vector:"<<*it<<endl;
     }
     vec.insert(vec.begin()+,);
     cout<<vec[]<<endl;
     vec.erase(vec.begin()+);
     cout<<vec[]<<endl;
     cout<<vec.size()<<endl;

     getch();
     return ;
 }