#include <opencv2/opencv.hpp>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <vector>

using namespace cv;
using namespace std;



int main()
{
    Mat original = imread("res.jpg",0);//0 because we need a grayscale image by default
    Mat modified;
    threshold(original, modified,200 ,255, CV_8UC1);//this is called a threshold function //8UC1 means single channel grey scale image(200 for center and 255 for outer circle)

    vector<vector<Point>> contours;
    //Here I find all the contours in my image
    findContours(modified.clone(),contours,RETR_EXTERNAL,CHAIN_APPROX_SIMPLE);

    vector<Point2f> centers;
    for( ; idx >= 0; idx = hierarchy[idx][0] )
    {
        //Then I draw them one by one on a different image and find their centers
        Mat dst(original.rows, original.cols, CV_8UC1, Scalar(0,0,0));
        drawContours( dst, contours, idx, color, CV_FILLED, 8, hierarchy );
        unsigned int nbPoints = 0; //this to count the nb of points of the current circle
        Point2f currentCenter(0,0); //This will contain the coordinates of the current center, that is the mean of all the points of the circle

        //I go through the image to find the points of the circle
        for(int x=0; x<dst.cols; x++) {
            for(int y=0; y<dst.rows; y++) {
                int val = dst.at<uchar>(y,x);// a single channel grey scale image (type 8UC1) and pixel coordinates x and y
                if( val>0) {//after thresholding,the picture will become black and white. Therefore,we will easily identify the white pixels(255) with the black pixels(0)
                  nbPoints++; //I increment because i found a point
                  currentCenter += Point2f(x,y); //I add the point to the center
                }
            }
        }
        currentCenter /= nbPoints; //I divide by the number of points to have a mean
        //I don't know what you want to do but here in current center you have the center of the current circle
        centers.push_back(); // I add it in a vector
    }

    //In centers you know have every center.

    waitKey(0);
    return 0;

}