OpenCV Video capture with Canny edges

#include <stdio.h>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>

using namespace cv;

int main( int argc, char** argv )
{
    VideoCapture cap(0);
    if( !cap.isOpened() ) {
        return 1;
    }

    Mat edges;

    namedWindow("edges",1);
    for(;;)
    {
        Mat frame;
        cap.read(frame); // get a new frame from camera
        cvtColor(frame, edges, CV_BGR2GRAY);
        GaussianBlur(edges, edges, Size(7,7), 1.5, 1.5);

        Canny(edges, edges, 0, 30, 3);
        imshow("edges", edges);
        if(waitKey(30) >= 0) break;
    }

    return 0;
}