#include <opencv2/opencv.hpp>
#include <opencv2/tracking.hpp>
#include <opencv2/core/ocl.hpp>

using namespace cv;
using namespace std;

// Convert to string
#define SSTR(x) static_cast<ostringstream &>((ostringstream() << dec << x)).str()

int main(int argc, char **argv)
{
    // List of tracker types in OpenCV 3.2
    // NOTE: GOTURN implementation is buggy and does not work.
    string trackerTypes[7] = {"BOOSTING", "MIL", "KCF", "TLD", "MEDIANFLOW", "GOTURN", "CSRT"};

    // Create a tracker
    string trackerType = trackerTypes[2];  // You can change the index to try different tracker types

    Ptr<Tracker> tracker;

#if (CV_MINOR_VERSION < 3)
    {
        tracker = Tracker::create(trackerType);
    }
#else
    {
        // Create a tracker based on the selected type
        if (trackerType == "BOOSTING")
            tracker = TrackerBoosting::create();
        if (trackerType == "MIL")
            tracker = TrackerMIL::create();
        if (trackerType == "KCF")
            tracker = TrackerKCF::create();
        if (trackerType == "TLD")
            tracker = TrackerTLD::create();
        if (trackerType == "MEDIANFLOW")
            tracker = TrackerMedianFlow::create();
        if (trackerType == "GOTURN")
            tracker = TrackerGOTURN::create();
        if (trackerType == "CSRT")
            tracker = TrackerCSRT::create();
    }
#endif

    // Read video
    VideoCapture video("videos/chaplin.mp4");

    // Exit if video is not opened
    if (!video.isOpened())
    {
        cout << "Could not read video file" << endl;
        return 1;
    }

    // Read first frame
    Mat frame;
    bool ok = video.read(frame);

    // Define initial bounding box
    Rect2d bbox(287, 23, 86, 320);

    // Uncomment the line below to select a different bounding box interactively
    // bbox = selectROI(frame, false);

    // Display initial bounding box
    rectangle(frame, bbox, Scalar(255, 0, 0), 2, 1);
    imshow("Tracking", frame);

    // Initialize the tracker with the selected bounding box
    tracker->init(frame, bbox);

    while (video.read(frame))
    {
        // Start timer
        double timer = (double)getTickCount();

        // Update the tracking result
        bool ok = tracker->update(frame, bbox);

        // Calculate Frames per second (FPS)
        float fps = getTickFrequency() / ((double)getTickCount() - timer);

        if (ok)
        {
            // Tracking success: Draw the tracked object
            rectangle(frame, bbox, Scalar(255, 0, 0), 2, 1);
        }
        else
        {
            // Tracking failure detected.
            putText(frame, "Tracking failure detected", Point(100, 80), FONT_HERSHEY_SIMPLEX, 0.75, Scalar(0, 0, 255), 2);
        }

        // Display tracker type on frame
        putText(frame, trackerType + " Tracker", Point(100, 20), FONT_HERSHEY_SIMPLEX, 0.75, Scalar(50, 170, 50), 2);

        // Display FPS on frame
        putText(frame, "FPS : " + SSTR(int(fps)), Point(100, 50), FONT_HERSHEY_SIMPLEX, 0.75, Scalar(50, 170, 50), 2);

        // Display frame.
        imshow("Tracking", frame);

        // Exit if ESC pressed.
        int k = waitKey(1);
        if (k == 27)
        {
            break;
        }
    }

    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}