Scope error in OpenCV C++ - c++

Question

I'm trying to compile the given OpenCV - C++ source code using g++ compiler the compiling command being:
g++ `pkg-config --cflags opencv` vehicleDetection.cpp `pkg-config --libs opencv`
I've also tried compiling the code by explicitly mentioning the libraries using
g++ -I/usr/local/include/opencv -I/usr/local/include/opencv2 -L/usr/local/lib/ -g -o vehicleDetection vehicleDetection.cpp -lopencv_core -lopencv_highgui -lopencv_video -lopencv_videoio -lopencv_videostab
It returns the error:
vehicleDetection.cpp: In function ‘int main()’:
vehicleDetection.cpp:96:2: error: ‘CascadeClassifier’ was not declared in this scope
CascadeClassifier vehicleCascade;
^
vehicleDetection.cpp:101:7: error: ‘vehicleCascade’ was not declared in this scope
if (!vehicleCascade.load (VEHICLE_CASCADE_NAME)) {
^
vehicleDetection.cpp:117:3: error: ‘vehicleCascade’ was not declared in this scope
vehicleCascade.detectMultiScale (grayscaleSampleVideo, vehicles,
^
vehicleDetection.cpp:118:22: error: ‘CV_HAAR_SCALE_IMAGE’ was not declared in this scope
1.1, 2, 0|CV_HAAR_SCALE_IMAGE,
^
vehicleDetection.cpp:121:3: error: ‘vehicleCount’ was not declared in this scope
vehicleCount = 0;
^
vehicleDetection.cpp:124:42: error: conversion from ‘int’ to non-scalar type ‘cv::Point {aka cv::Point_<int>}’ requested
vehicles[i].y + vehicles[i].height);
^
vehicleDetection.cpp:126:45: error: conversion from ‘int’ to non-scalar type ‘cv::Point {aka cv::Point_<int>}’ requested
Point pt2 = (vehicles[i].x, vehicles[i].y);`
May someone enlighten me with the errors.
I beg pardon for disturbing with such trifle issues.
The source code is given herein-
#include <iostream>
#include <string>
#include "opencv2/core/core.hpp"
#include "opencv2/core/core_c.h"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/highgui/highgui_c.h"
#include "opencv2/video/video.hpp"
#include "opencv2/videoio/videoio.hpp"
#include "opencv2/videoio/videoio_c.h"
using namespace std;
using namespace cv;
#define VEHICLE_CASCADE_NAME "path to cascade.xml"
#define SAMPLE_VIDEO_NAME "path to sample video"
#define WINDOW_NAME "Vehicle Detector"
int main () {
int timeCount = 0;
CascadeClassifier vehicleCascade;
Mat captureSampleVideo, grayscaleSampleVideo;
cout << "\nVehicle Detection" << endl << "NOTE: Press <Esc> to quit" << endl;
if (!vehicleCascade.load (VEHICLE_CASCADE_NAME)) {
cout << "ERROR: Classifier loading unsuccessful!!" << endl;
}
VideoCapture sampleVideo (SAMPLE_VIDEO_NAME);
if (!sampleVideo.isOpened ()) {
cout << "ERROR: Sample video loading unsuccessful!!" << endl;
}
while (1) {
sampleVideo >> captureSampleVideo;
cvtColor (captureSampleVideo, grayscaleSampleVideo, CV_BGR2GRAY);
equalizeHist (grayscaleSampleVideo, grayscaleSampleVideo);
vector<Rect> vehicles;
vehicleCascade.detectMultiScale (grayscaleSampleVideo, vehicles,
1.1, 2, 0|CV_HAAR_SCALE_IMAGE,
Size(30, 30));
vehicleCount = 0;
for (int i = 0; i < vehicles.size(); i++) {
Point pt1 = (vehicles[i].x + vehicles[i].width,
vehicles[i].y + vehicles[i].height);
Point pt2 = (vehicles[i].x, vehicles[i].y);
rectangle (captureSampleVideo, pt1, pt2,
CvScalar(255, 0, 0), 1, 8, 0);
vehicleCount += 1;
}
namedWindow (WINDOW_NAME, WINDOW_NORMAL);
imshow (WINDOW_NAME, captureSampleVideo);
if (waitKey(1) == 27) {
destroyWindow (WINDOW_NAME);
cout << timeCount << " ms" << endl;
break;
return 0;
}
}
}