I want to create interface and run within button click

edit

I want to count the pedestrian amount from image.so it's working. now i have to do within button click. if i click button, this function want to run and count the pedestrian. my codes here. how can i do that. help me.

#include "stdafx.h"
#include <stdio.h>
#include <cv.h>
#include <iostream>
#include <highgui.h>

using namespace cv;
using namespace std;
void detect(IplImage *faces);
int main()
{
  freopen("out.txt","w",stdout);
  CascadeClassifier cascade;

  if (!cascade.load("haarcascade_frontalface_alt.xml"))
    return -1;

  Mat src = imread("people1.jpg");
  if (src.empty())
    return -1;

  Mat gray;
  cvtColor(src, gray, CV_BGR2GRAY);
  equalizeHist(gray, gray);

  vector<Rect> faces;
  cascade.detectMultiScale(gray, faces, 1.2, 3);

  for (int i = 0; i < faces.size(); i++)
  {
    Rect r = faces[i];
    rectangle(src, Point(r.x, r.y), Point(r.x + 5, r.y + 5), CV_RGB(0,255,0));
  }
  std::cout << "Total: " << faces.size() << " faces" << std::endl;
  imshow("src", src);
  waitKey(0);

  return 0;

}