If you use the openCV library for programming on the desktop, how to display the image on the screen (window)?

edit

#include <exception>
#include <iostream>    

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

int main()
{
  try{
    cv::Mat input = cv::imread("aaa.jpg");
    if(input.empty()){
       std::cerr<<"can't open image"<<std::endl;
       return -1;
    }

    cv::imshow("", input);
    cv::waitKey();
  }catch(std::exception const &ex){
     std::cerr<<ex.what()<<std::endl;
  }
}

Hope this is what you are finding, if you need a text book to study openCV, give this a try, many useful algorithms and functions are introduced by this book.