How to Install Ubuntu and VirtualBox on a Windows PC

In this project, we will get started on our Robot Operating System (ROS) programming journey by installing Ubuntu. Ubuntu is a popular distribution (i.e. flavor) of the Linux operating system and is fully supported by ROS, the most popular framework for writing robotics software. If you have a Windows PC (I have Windows 10), I recommend you install a VirtualBox first and then install Ubuntu in the Virtual Box. I’ll show you how to do all that below.

The process for installing Ubuntu has a lot of steps, so hold on tight, don’t give up if something goes wrong, and go slowly so that you get your installation setup properly. Let’s get started!

Requirements

Here are the project requirements:

  • Install Ubuntu
  • Install Virtual Box
  • Install Ubuntu on VirtualBox
  • Learn Important Linux Terminal Commands

You Will Need

The following components are used in this project. You will need:

Directions

Download the Ubuntu Image

Check Ubuntu Releases to find the latest version of Ubuntu that has long term support (LTS). As of this writing, the latest release is Ubuntu 18.04.3 LTS (Bionic Beaver).

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Click on the latest release of Ubuntu, and download the 64-bit PC (AMD64) desktop image (.iso file).

Before installing Ubuntu, you need to install Virtual Box. Virtual Box extends the capabilities of your host computer (i.e. your laptop or desktop PC) by enabling you to install and run an operating system in a new environment on top of your current operating system (Windows 10 in my case). The environment the new operating system will run in is known as a virtual machine (or guest).

Install VirtualBox

Let’s download VirtualBox. Go to VirtualBox downloads.

Select the platform package for Windows hosts to download the executable (.exe) file.

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Detailed installation instructions for all operating systems (Windows, Mac OS, Linux, and Solaris) can be found in the instruction manual. Let’s go through the steps.

Double-click on the executable file.

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Click Next to begin the installation process.

Click Next to install the VirtualBox in the default location.

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Click Next to choose the default features.

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You will see a warning about network interfaces. Ignore it, and click Yes to proceed.

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You are now ready to install VirtualBox. Click Install to proceed.

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Click Yes to allow the software to make changes to your device.

Click Install again.

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Click Finish to run VirtualBox.

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You can optionally delete the original executable file for VirtualBox (the one with the .exe extension). You don’t need it anymore.

Create a Virtual Machine

Now that VirtualBox is installed on your computer, we need to now create a new virtual machine.

Click the New button in the toolbar.

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Type in a descriptive name for your operating system. You can stick with the default machine folder. The machine folder is where your virtual machines will be stored.

Also, select the operating system that you want to later install (Linux in this case).

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Click Next to proceed.

The default memory size for me is 1024 MB. That is not enough. Raise it to 6470 MB, and then click Next to proceed.

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Make sure “Create a virtual hard disk now” is selected, and click Create.

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Select “VirtualBox Disk Image (VDI)”, and click Next.

Choose a Fixed size virtual hard disk so that you have better performance, and click next.

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You can stick with the default hard disk space (10GB as of the time of this writing) or go with something like 50 GB. I went with 50 GB. I also prefer to save my hard disk on my D drive (which has more space than my C drive). Then click Create.

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Double-click on the left panel where it says “Ubuntu 18.04.” A startup window will appear.

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Click the Folder icon next to Empty and select the Ubuntu image you downloaded earlier in this tutorial. It is a .iso file. You can make sure that your .iso file is somewhere in your C drive (doesn’t have to be on your Desktop). Then click Start to proceed.

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You might get an error that looks like this.

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Click Close VM.

Enable Virtualization Technology on Your Computer

The error above arises because virtualization technology is disabled on your computer by default. We need to enable it. Let’s do that now.

Go down to the search area on your computer in the bottom left of your screen, and searched for “Advanced Startup”.

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Click “Change Advanced Startup Options.”

Click Restart Now.

Click Troubleshoot.

Click Advanced Options.

Click UEFI Firmware Settings.

Click Restart to change the UEFI Firmware Settings.

Click F10 BIOS Setup.

Press the right arrow to go to System Configuration.

Scroll down to Virtualization Technology.

Press Enter to select Enabled.

Press the down arrow and then Enter to select Enabled.

Press F10 to save and exit.

Press Enter on Yes to save the changes.

Your computer will reboot.

Double-click on the VirtualBox icon to start it.

Click on the left panel of the window to start the Ubuntu virtual machine. Or you can just click Start in the toolbar.

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You should see the Ubuntu window appear.

Install Ubuntu

Click on “Install Ubuntu” to install Ubuntu.

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Click “Continue” to save the keyboard layout. The default English one is fine.

Keep clicking Continue through all the prompts. The options you want selected as you go through the prompts are the following:

  • Download updates while installing Ubuntu
  • Erase disk and install Ubuntu

You will get to a point where you will need to set your time zone. It will be a big map of the world that should automatically detect your location.

Type in a computer name and pick a username and password. I select the “Log in automatically” option.

When installation is complete, click “Restart Now.”

When you reboot, you will go to the Ubuntu desktop.

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If at any time you want to exit Ubuntu, go to File → Close. You will be given the option to save your machine state so that you can pick up where you left off the next time you login to Ubuntu.

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Two additional notes….when you power up your VirtualBox, it is a good idea to go to Settings → Display and change your Video Memory to 128 MB. This will give you ample video memory.

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Also go to Settings → System → Processor, and adjust the number of CPUs to 4.

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If you at any point in the future run out of hard drive space for your virtual machine, you can move it to another drive (e.g. D drive) by following this article at Tech Republic.

Here are the complete settings on my Windows machine.

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Getting Used to Ubuntu

Similar to the C drive in Windows 10, Linux has a file system (everything branches from the / symbol). You can find it by clicking the icon of the file cabinet on the right side of the desktop. It is the third icon down in the image below.

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Click “Other Locations.”

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Click “Computer.”

You will see all the files. For example, the path to the bin file is /bin 

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You can find popular software applications for download in the Ubuntu Software module. It is the sixth icon in the left-hand panel. 

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Linux Terminal Commands With the Ubuntu Command-Line Interface

We could certainly navigate around Ubuntu using the graphical user interface, but we would miss out on being able to run advanced processes for ROS. This is where the Terminal application comes in handy. The Terminal application is the Ubuntu command-line interface and is similar to the Command Prompt on a Windows 10 system. It enables us to use Linux terminal commands.

To open the Terminal, click the bottom left where you see those nine white dots and search for “Terminal” at the top. 

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Click on Terminal.

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If you do a Google search for “common Linux terminal commands,” you should find some nice cheat sheets to use as a reference. Let’s try a few common commands below.

The following command retrieves a list of all the files and folders in the current directory.

ls
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If you want to change to the desktop, type:

cd Desktop

If you want to get the path to the current directory, type:

pwd

To go up one directory, type:

cd ~

To update the list of packages, type:

sudo apt-get update

The sudo keyword enables you to run a command as an administrator.

At this stage, it would be useful for you to install htop, an interactive system-monitor process-viewer and process-manager. To install it, type the following command:

sudo apt-get install htop

If at any point you want to remove it, you can type the following command:

sudo apt-get remove htop

To run, htop, you type:

htop

You can reboot the system using the following command:

sudo reboot

Finally, to shutdown the system, you type the following command:

sudo poweroff

How to Set Up Anaconda for Windows 10

In this post, I will show you how to set up Anaconda. Anaconda is a free, open-source distribution of Python (and R). The goal of Anaconda is to be a free “one-stop-shop” for all your Python data science and machine learning needs. It contains the key packages you need to build cool machine learning projects.

Requirements

Here are the requirements:

  • Set up Anaconda.
  • Set up Jupyter Notebook.
  • Install important libraries.
  • Learn basic Anaconda commands.

Directions

Install Anaconda

Go to the Anaconda website and click “Download.”

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Choose the latest version of Python. In my case, that is Python 3.7. Click “Download” to download the Anaconda installer for your operating system type (i.e. Windows, macOS, or Linux). 

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Follow the instructions to install the program:

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Verify Anaconda is installed by searching for “Anaconda Navigator” on your computer.

Open Anaconda Navigator.

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Follow the instructions here for creating a “Hello World” program. You can use Spyder, Jupyter Notebooks, or the Anaconda Prompt (terminal). If you use Jupyter Notebooks, you will need to open the notebooks in Firefox, Google Chrome or another web browser.

Check to make sure that you have IPython installed. Use the following command (in an Anaconda Prompt window) to check:

where ipython
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Make sure that you have pip installed. Pip is the package management system for Python.

where pip
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Make sure that you have conda installed. Conda is Anaconda’s package management system.

where conda
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Install Some Libraries

Install OpenCV

To install OpenCV, use the following command in the Anaconda Prompt:

pip install opencv-contrib-python

Type the following command to get a list of packages and make sure opencv-contrib-python is installed.

conda list

Install dlib

Install cmake.

pip install cmake

Install the C++ library called dlib

pip install dlib
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Type the following command and take a look at the list to see if dlib is successfully installed:

conda list

Install Tesseract

Go to Tesseract at UB Mannheim.

Download the Tesseract for your system.

Set it up by following the prompts.

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Once Tesseract OCR is downloaded, find it on your system.

Copy the name of the file it is located in. In my case, that is:

C:\Program Files\Tesseract-OCR

Search for “Environment Variables” on your computer.

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Under “System Variables,” click “Path,” and then click Edit.

Add the path: C:\Program Files\Tesseract-OCR

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Click OK a few times to close all windows.

Open up the Anaconda Prompt.

Type this command to see if tesseract is installed on your system.

where tesseract

Now, apply the Python binding to the packages using the following commands:

pip install tesseract
pip install pytesseract

Install TensorFlow

Type the following command in the Anaconda Prompt:

pip install tensorflow

Install TensorFlow hub using this command:

pip install tensorflow-hub

Now install tflearn.

pip install tflearn

Now, install the Keras neural network library.

pip install keras

Install the Rest of the Libraries

Type the following commands to install the rest of the libraries:

pip install pillow
pip install SimpleITK

Learn Basic Anaconda Commands

Changing Directories

If you ever want to change directories to the D drive instead of the C drive, open Anaconda Prompt on your computer and type the following commands, in order

D:
cd D:\XXXX\XXXX\XXXX\XXXX

where D:\XXXX\XXXX\XXXX\XXXX is the file path.

Listing Directory Contents

Type the dir command to list the contents of a directory.

dir

Creating a Jupyter Notebook

Open Anaconda Prompt on your computer and type the following command:

jupyter notebook

Converting a Jupyter Notebook into Python Files

If you want to convert a Jupyter Notebook into Python files, change to that directory and type the following command:

jupyter nbconvert --to script *.ipynb

Congratulations if you made it this far! You have all the libraries installed that you need to do fundamental image processing and computer vision work in Python.

Difference Between Recursion and Iteration

If you are learning algorithms or data structures, you might have come across the terms recursion and iteration. Knowing the difference between the two can be confusing, so I will explain both terms using a real-world example.

Eating My Morning Bowl of Oatmeal

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Everyday before I go to work, I take a shower, get dressed, and then head over to the kitchen to fix myself a big bowl of oatmeal. Breakfast is my favorite meal of the day and the most important. Many days I feel like skipping breakfast so that I can go on with my day. However, on those rare occasions when I decide to skip breakfast, I have usually regretted it. I spend the morning hungry and cannot fully concentrate on the tasks at hand.

The problem of eating my morning bowl of oatmeal can be implemented both iteratively and recursively. Iteration is the act of repeating a process. So, in the case of oatmeal, an iterative way to solve the problem of eating my bowl of oatmeal would be to do the following:

  1. Take one bite of the oatmeal
  2. Repeat Step 1 until the bowl is empty.

Recursion, on the other hand, is when a method calls itself. It involves breaking a problem into smaller versions of the same problem until you reach a trivial stopping case.

Let’s consider the problem of eating a bowl of oatmeal. I can solve the problem of eating the entire bowl of oatmeal recursively by breaking it into two subproblems as follows:

  • Take one bite of oatmeal
  • Eat the rest of the bowl of oatmeal

Each step of this recursive procedure gets smaller and smaller until all I am left with is one more spoonful of oatmeal. Once I finish that last spoonful, I am done, and I can go on about my day.

Here is how I would implement the iterative and recursive procedures for eating a bowl of oatmeal in Java pseudocode:

Iterative Implementation

public static main void main(String[] args) {

    while (!bowl.empty()) {
        bowl.takeOneBite(); 
        // Keep taking bites over and over 
        // again until the bowl of oatmeal 
        // is empty
    }
}

Recursive Implementation

public static void eatOatmeal(Bowl bowl) {

    if (bowl.empty()) {  
    // This is our stopping case. 
    // We stop taking bites once 
    // the bowl is empty

        return;  
    }
    else {
        bowl.takeOneBite(); 
        eatOatmeal(bowl); // Recursive call
    }
}

What Is a Maximum Spanning Tree?

In this post, I will explain the concept of a maximum spanning tree.

What is a Spanning Tree?

Let’s say we have a graph G with three nodes, A, B, and C. Each node represents an attribute. For example, for a classification problem for breast cancer, A = clump size, B = blood pressure, C = body weight.

Graph G:

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A spanning tree is a subset of the graph G that includes all of the attributes with the minimum number of edges (that would have to be 2 because a tree with just one edge would only connect at most 2 attributes). In the graph above, there are three spanning trees. All spanning trees in this graph G must have the same number of attributes (3 in total) and edges (2 in total).

Spanning Tree 1:

Spanning Tree 2:

Spanning Tree 3:

What is a Maximum Spanning Graph?

OK, so we have our spanning trees. Now, imagine that each edge has a weight. This weight would be some number. Weighted graphs look like this:

The graph above could has three spanning trees, subsets of the graph G that include all of the attributes with the minimum number of edges.

Which one of those spanning graphs is the “maximum spanning graph?”…the one that, when you add up the weights of each edge of the spanning graph, delivers the greatest result. The answer to that is our maximum spanning tree.

Here is the maximum spanning tree:

Since the Attribute Designated as the Root Is Arbitrary, Is It Safe to Assume That This Choice Does Not Affect the Model Effectiveness?

Yes, it is safe to assume that. The graph doesn’t change, and Kruskal’s algorithm, the algorithm for finding the maximum spanning tree in a graph doesn’t care what the root is…it just wants to find the largest edge at each step that doesn’t produce a cycle.

The number of maximum spanning trees in a graph G remains constant. Whether you start at C, B, and E, doesn’t matter. The graph is what it is…unless of course you decide to add a new attribute…but then it would be a different graph with a whole other set of spanning trees.

How to Set Up Visual Studio Community 2019 for Windows 10

In this post, I’ll show you how to set up Visual Studio Community 2019 for Windows 10. This IDE will help us build C++ and Python programs. Our goal is to create a simple “Hello World” program in C++ and in Python.

Requirements

Here are the requirements:

  • Set up Visual Studio Community 2019 for Windows 10.
  • Create a simple “Hello World” program in C++ and in Python

Directions

Installation of Visual Studio Community 2019

Open a web browser.

Type “download visual studio community” into your favorite search engine.

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Click on the first result.

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Click to download Visual Studio Community.

Click the up arrow (^) and then click “Show in folder.”

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Right click on the file and click “Run as administrator.”

Click Yes.

Acknowledge the terms and conditions by clicking “Continue”.

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Wait for the Visual Studio Installer to do its thing.

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Select “Desktop Development with C++”. This is all you need to build C++ programs.

Select “Python development”. This is all you need to build Python programs.

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I also plan to develop for Raspberry Pi and do some data science, so I installed some extra workloads. This is optional if all you want to do is develop programs in C++ and Python:

  • Linux development with C++
  • Data science and analytical applications
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Choose the individual components that you want to install. It is OK to keep the default. Here is what else I selected:

  • Git for Windows
  • GitHub extension for Visual Studio
  • Class Designer (under Code Tools)
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You don’t need any of the .Net stuff.

Click “Install”. Go get a bite to eat or take a break. This will take a while.

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Once the install is complete, reboot your computer.

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Search for the program “Visual Studio 2019” on your computer, and then create a Desktop shortcut for it so that it is easier to find the next time around.

On the sign-in screen, sign in using your Microsoft account (or create one).

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Select “General”.

Creating the “Hello World!” Program in C++

Click “Create a new project”.

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Click “Empty Project” to start a new project.

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Configure your new project.

Right click on the project under the Solution Explorer. Go to Add -> New Item.

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Select C++ File (.cpp), and give the source code a name. Then click “Add”.

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Type in the code for your “Hello World!” program:

// This is a basic C++ program to display "Hello World!" 

// Header file for input output functions 
#include<iostream>  

using namespace std;

// main function: where the execution of program begins 
int main()
{
	// prints Hello World! to the console
	cout << "Hello World!";

	return 0;
}

Click the green button (Local Windows Debugger) to compile and run.

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You can also go to Build -> Build Solution. Then go to Debug -> Start Without Debugging.

That’s it! You should see the Hello World! message pop up.

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Running a Program in a Command Window

Solution Explorer (Right click the project name) -> Open Folder in File Explorer

Open the Debug folder.

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Select the hello_world.exe application.

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Hold down the Shift Key and right click to open a menu

Choose “Copy as path”.

Press Windows + R to open a command prompt window.

Type cmd.exe in the box.

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Click OK.

Right click to paste in the path.

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Press Enter to run.

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Creating the “Hello World!” Program in Python

Click “Create a new project”.

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Under “Language” select Python.

Select “Python Application”.

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Configure your new project. This time I checked “Place solution and project in the same directory”.

Click “Create”.

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Type in the code for your “Hello World!” program:

print("Hello World!")

Click the green button (“Attach”) to run.

That’s it! You should see the message pop up.

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To run via command line, go to the project folder and find the python file (hello_world.py in this case).

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Hold down the Shift Key and right click to open a menu.

Choose “Copy as path”.

Press Windows + R to open a command prompt window.

Right click to paste in the path.

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Press Enter to run. You might have to select the Python application you want to use to execute the file. You’ll only have to do this once.

The message should print to the terminal window. Congratulations! You are now ready to build C++ and Python programs!

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How to Add an External C++ Library to Your Project

Libraries in C++ are collections of code that someone else wrote. They prevent you from having to reinvent the wheel when you need to implement some desired functionality. You can think of libraries as a plugin or add-on that gives you more functionality.

For example, I wanted to write a program that is able to multiply two matrices together. Instead of writing the code from scratch, I searched the web for a linear algebra library in C++ that contained functionality for multiplying matrices. I found the library named “Eigen.” I added the library to my project in the CodeLite IDE, and I was ready to go.

Without further ado, here is the step-by-step process for adding an external C++ library to your project using the CodeLite IDE. Note that this process will be different if you are using another IDE for C++, but the two basic steps are the same:

  1. Add the path for the header files
  2. Add the path for the actual code (i.e. the library)

How to Add an External C++ Library to Your Project

Step 1: Go to the website of the library.
For example, for the linear algebra library, Eigen, you go to this page: Eigen Main Page

Step 2: Download the zip file that contains all the code.

Step 3: Unzip the zip file to your computer.

Step 4: Open CodeLite (i.e. your IDE)

Step 5: Open a new Project

Step 6: Right click on project name and click on Settings

Step 7: Click the Compiler tab and add the Include Paths:
e.g. the folder that contains the folder named ‘Eigen’…C:\XYZ\eigen-eigen-21301928\
This is where the compiler can find the .h (i.e. header) files

Step 8: Click Linker and add the Libraries Search Path
e.g. C:\XYZ\eigen-eigen-21301928\
The path above needs to be the location where the linker can find the libraries (usually suffixed with .a, .dll, .lib, .so)

  • Static Libraries are – XYZ.lib for Windows, UNIX/Linux/Max – libXYZ.a
  • Dynamic Libraries are – XYZ.dll for Windows, Unix/Linux/Mac – libXYZ.so

Step 9: Go to main.cc (i.e. your source code file…could also be main.cpp) and add the preprocesser directives at the top of the source file:

e.g.
#include <Eigen/Dense>
#include <Eigen/Sparse>
#include

using namespace Eigen;

[Your code here]

Step 10: That’s it. You are ready to rock and roll!

How to Learn Git and Github for Windows Users

Most of the tutorials and books on Git and GitHub are overly complicated. The best book that I have found that covers all the fundamentals is A Practical Guide to Git and GitHub for Windows Users: From Beginner to Expert in Easy Step-By-Step Exercises by Roberto Vormittag. It explains everything step-by-step and covers the main use cases. It is easy to follow, and you can get through the entire book in just a day.