C++ opencv Hough Line

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv)
{
Mat frame;
Mat dst, cdst;

VideoCapture cap(0);
while (1)
{
cap >> frame;
//Detecting the edges
Canny(frame, dst, 50, 200, 3);

//Converting to grey scale
cvtColor(dst, cdst, CV_GRAY2BGR);

#if 0
vector<Vec2f> lines;
HoughLines(dst, lines, 1, CV_PI / 180, 100, 0, 0);

for (size_t i = 0; i < lines.size(); i++)
{
float rho = lines[i][0], theta = lines[i][1];
Point pt1, pt2;
double a = cos(theta), b = sin(theta);
double x0 = a*rho, y0 = b*rho;
pt1.x = cvRound(x0 + 1000 * (-b));
pt1.y = cvRound(y0 + 1000 * (a));
pt2.x = cvRound(x0 - 1000 * (-b));
pt2.y = cvRound(y0 - 1000 * (a));
line(cdst, pt1, pt2, Scalar(0, 0, 255), 3, CV_AA);
}
#else
vector<Vec4i> lines;
HoughLinesP(dst, lines, 1, CV_PI / 180, 50, 50, 10);
for (size_t i = 0; i < lines.size(); i++)
{
Vec4i l = lines[i];
line(cdst, Point(l[0], l[1]), Point(l[2], l[3]), Scalar(34, 139, 34), 3, CV_AA);
}
#endif
imshow("source", frame);
imshow("detected lines", cdst);
if (waitKey(30) == 27)
break;
}

return 0;
}