printf FPS in opencv

FPS.cpp

cv::VideoCapture cap(0); // open the default camera
if(!cap.isOpened()) // check if we succeeded
{
	printf("Camera open error.\n");
	return -1;
}
char strfps[64] = "0 fps";
clock_t start = clock();
unsigned int fps = 0;
for(;;)
{
	cap >> image;
	detect_face(image, cascade, nestedCascade, scale);
	fps++;
	if(clock() - start > CLOCKS_PER_SEC)
	{
		sprintf(strfps, "%d fps", fps);
		fps = 0;
		start = clock();
	}
	putText(image, strfps, cv::Point(0,20), 3, 1, CV_RGB(25,200,25));
}