My simple code doesnt work, it says CV_WINDOWS_NORMAL is an undeclared identifier, what should I do, is there some other lib that I need to include?

edit

Code:

#include <iostream>
#include <stdio.h> 
#include <stdlib.h>

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

using namespace std;
using namespace cv;

int main(int argc, char** argv)
{

    VideoCapture capture(0);

    if (argc == 1 && capture.isOpened() == false)
    {
        cerr << "Cannot capture images from the web camera ..." << endl;
        return -1;
    }

    namedWindow("original", CV_WINDOW_NORMAL);
    namedWindow("processed", CV_WINDOW_NORMAL);
    namedWindow("blurred", CV_WINDOW_NORMAL);

    Mat frame;
    Mat grayImage;
    Mat processedImage;
    Mat bluredImage = frame;
    //bluredImage = Scalar::all;
    for (int keyCode = -1; keyCode < 0; )
    {
        if (argc == 1)
            capture >> frame;
        else
            frame = imread(argv[1], CV_LOAD_IMAGE_COLOR);

        if (frame.empty() == true)
            break;

        cvtColor(frame, grayImage, CV_BGR2GRAY);

        //TODO: Add the selected image processing function calls ...
        cvtColor(frame, processedImage, CV_BGR2GRAY); // This should be replaced!

        medianBlur(frame, bluredImage, 3);

        imshow("original", frame);
        imshow("processed", processedImage);
        imshow("blurred", bluredImage);


        if (argc == 1)
            keyCode = waitKey(10) % 256;
        else
            keyCode = waitKey(0) % 256;
    }



    destroyWindow("original");
    destroyWindow("processed");
}