I want to capture video from webcam, but window disappears after capturing one frame

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Hi. I'm trying to capture video from my webcam via OpenCV C++. The program works fine, but the window terminates after displaying just one frame. I've tried Python examples as well on my computer, and they work as advertised. Help please.

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
using namespace cv;
using namespace std;

int main()
{
    VideoCapture stream1(0);   //0 is the id of video device.0 if you have only one camera.
    if (!stream1.isOpened())//check if video device has been initialised
        cout << "cannot open camera";
    //unconditional loop
    while (true)
    {
        Mat cameraFrame;
        stream1.read(cameraFrame);
        imshow("cam", cameraFrame);
        if (waitKey(0) >= 0)
            break;
    }
    return 0;
}