Sommaire pour Vol 2 2022 de Coding User

C++ is an amazing programming language. Most of what you see in front of you when you power up your computer, regardless of whether you’re using Windows, macOS or Linux, is created using C++. Being able to code in C++ will open a whole new world for you, in terms of desirable professional skills and the ability to code amazing apps and games. C++ is an efficient and powerful language that’s used to develop operating systems, applications, games and much more. It’s used in science, engineering, banking, education, the space industry, and much more. How to Set Up C++ in Windows How to Set Up C++ on a Mac How to Set Up C++ in Linux Other C++ IDEs to Install…

LINUX++ There are many different versions of Linux available, for this example we’re using one of the more popular distributions: Linux Mint. However, these steps will work in any Debian-based Linux. STEP 1 The first step with ensuring Linux is ready for your C++ code is check the system and software are up to date. Open a Terminal and enter: sudo apt-get update && sudo apt-get upgrade. Press Return and enter your password. These commands updates the entire system and any installed software. STEP 2 Most Linux distros come preinstalled with all the necessary components to start coding in C++. However, it’s always worth checking to see if everything is present, so still within the Terminal, enter: sudo apt-get install build-essential and press Return. If you have the right components,…

INSTALLING PYTHON 3.X Microsoft Windows doesn’t come with Python pre-installed as standard, so you’re going to have to install it yourself manually. Thankfully, it’s an easy process to follow. STEP 1 Start by opening your web browser to www.python.org/downloads/. Look for the button detailing the Download link for Python 3.x. Python is regularly updated, changing the last digit for each bug fix and update. Therefore, don’t worry if you see Python 3.7.0, or more, as long as it’s Python 3, the code in this book will work fine. STEP 2 Click the download button for version 3.x, and save the file to your Downloads folder. When the file is downloaded, double-click the executable and the Python installation wizard will launch. From here you’ll have two choices: Install Now and Customise…

Linux is such a versatile operating system that’s both malleable and powerful, while offering the programmer a perfect foundation on which to build their skills. While all the popular and mainstream programming languages are available on Linux, as they are on Windows and macOS, Linux also utilises its own coding language, called scripting. In this section, we’ll take you through the basics as you first start to use this incredible coding language. Installing Linux in a Virtual Environment Getting Ready to Code in Linux Did You Know? Creating Bash Scripts - Part 1 Creating Bash Scripts - Part 2 Creating Bash Scripts - Part 3 Creating Bash Scripts - Part 4 Creating Bash Scripts - Part 5 Command Line Quick Reference…

IF, THEN, ELSE With most programming structures there will come a time where you need to loop through the commands you’ve entered to create better functionality, and ultimately a better program. STEP 1 Let’s look at the If, Then and Else statements now, which when executed correctly, compare a set of instructions and simply work out that IF something is present, THEN do something, ELSE do something different. Create a new script called greeting2.sh and enter the text in the screenshot below into it. STEP 2 Greeting2.sh is a copy of greeting.sh but with a slight difference. Here we’ve added a loop starting at the if statement. This means, IF the variable entered is equal to David the next line, THEN, is the reaction to what happens, in this case…

TOP 10 COMMANDS These may not be the most common commands used by everyone but they will certainly feature frequently for many users of Linux and the command line. cd The cd command is one of the commands you will use the most at the command line in Linux. It allows you to change your working directory. You use it to move around within the hierarchy of your file system. You can also use chdir. ls The ls command shows you the files in your current directory. Used with certain options, it lets you see file sizes, when files where created and file permissions. For example, ls ~ shows you the files that are in your home directory. cp The cp command is used to make copies of files and…

GREETINGS FROM C++ Compiling and executing C++ code from Code::Blocks is extraordinarily easy; it’s just a matter of clicking an icon and seeing the result. Here’s how it’s done. STEP 1 Open Code::Blocks, if you haven’t already, and load up the previously saved Hello World code you created. Ensure that there are no visible errors, such as missing semicolons at the end of the std::cout line. STEP 2 If your code is looking similar to the one in our screenshot, then look to the menu bar along the top of the screen. Under the Fortran entry in the topmost menu you can see a group of icons: a yellow cog, green play button and a cog/play button together. These are Build, Run, Build and Run functions. STEP 3 Start by…

C++ = MC2 The basic mathematical symbols apply in C++ as they do in most other programming languages. However, by using the C++ Math Library, you can also calculate square roots, powers, trig and more. STEP 1 C++’s mathematical operations follow the same patterns as those taught in school, in that multiplication and division take precedence over addition and subtraction. You can alter that though. For now, create a new file and enter: #include <iostream> using namespace std; int main () { float numbers = 100; numbers = numbers + 10; //This adds 10 to the initial 100 cout << numbers << “\n”; numbers = numbers - 10; //This subtracts 10 from the new 110 cout << numbers << “\n”; } STEP 2 While simple, it does get the old…

STARTING PYTHON As when learning anything new, you need to start slow. You can pick up the pace as your experience grows, but for now, let’s just get something appearing on the screen. Don’t worry, you’ll soon be coding like a pro! STEP 1 Click on the Windows Start button, and start typing ‘idle’. The result will be the currently installed version of the Python IDLE on your system. You can Pin it to the Start for convenience, otherwise simply click the icon to launch the Python Shell. STEP 2 The Shell is where you can enter code and see the responses and output of code you’ve programmed into Python. This is a kind of sandbox, if you will, where you’re able to try out some simple code and processes.…

COMMAND THE CODE Using the code we created in the previous tutorial, the one we named hello.py, let’s see how we can run code that was made in the GUI at the command line level. STEP 1 When you first installed Python, the installation routine automatically included all the necessary components to allow the execution of code outside of the GUI IDLE; in other words, the command line. To begin with, click on the Windows Start Button, and type: cmd. STEP 2 As you did when launching the Python IDLE, click on the returned result from the search, the Command Prompt App. This will launch a new window, with a black background and white text. This is the command line, also called a Terminal in macOS, Linux, and Raspberry Pi…

CODE::BLOCKS Code::Blocks is a free C++, C and Fortran IDE that is feature rich and easily extendible with plugins. It’s easy to use, comes with a compiler and has a vibrant community behind it too. STEP 1 Start by visiting the Code::Blocks download site, at www.codeblocks.org/downloads. From there, click on the ‘Download the binary releases’ link to be taken to the latest downloadable version for Windows. STEP 2 There you can see, there are several Windows versions available. The one you want to download has mingw-setup.exe at the end of the current version number. At the time of writing this is: codeblocks-17.12mingw-setup.exe. The difference is that the mingw-setup version includes a C++ compiler and debugger from TDM-GCC (a compiler suite). STEP 3 When you’ve located the file, click on the…

DEVELOPING C++ Here are ten great C++ IDEs that are worth looking into. You can install one or all of them if you like, but find the one that works best for you. ECLIPSE Eclipse is a hugely popular C++ IDE that offers the programmer a wealth of features. It has a great, clean interface, is easy to use and available for Windows, Linux and Mac. Head over to www.eclipse.org/downloads/ to download the latest version. If you’re stuck, click the Need Help link for more information. GNAT The GNAT Programming Studio (GPS) is a powerful and intuitive IDE that supports testing, debugging and code analysis. The Community Edition is free, whereas the Pro version costs; however, the Community Edition is available for Windows, Mac, Linux and even the Raspberry Pi.…

PYTHON PENGUIN Linux is such a versatile operating system that it’s often difficult to nail down just one-way of doing something. Different distributions go about installing software in different ways, so for this particular tutorial we will stick to Linux Mint. STEP 1 First you need to ascertain which version of Python is currently installed in your Linux system. To begin with, drop into a Terminal session from your distro’s menu, or hit the Ctrl+Alt+T keys. STEP 2 Next, enter: python --version into the Terminal screen. You should have the output relating to version 2.x of Python in the display. Most Linux distro come with both Python 2 and 3 by default, as there’s plenty of code out there still available for Python 2. Now enter: python3 --version. STEP 3…

CREATING THE VM There are plenty of options to choose from when creating a VM. For now though, we’ll setup a VM adequate to run the excellent Linux Mint, and perform well. STEP 1 With VirtualBox open, click on the New icon in the top-middle of the right-hand panel of the app. This will open the new VM Wizard. STEP 2 In the box next to Name type Linux Mint, and VirtualBox should automatically choose Linux as the Type and Ubuntu (64-bit) as the Version, if not then use the drop-down boxes to select the correct settings (remember Mint mainstream is based on Ubuntu). Click Next when you’re ready to proceed. STEP 3 The next section will define the amount of system memory, or RAM, the VM has allocated. Remember…

GET SCRIPTING A Bash script is simply a series of commands that Mint will run through to complete a certain task. They can be simple or remarkably complex, it all depends on the situation. STEP 1 You’ll be working within the Terminal and with a text editor throughout the coming pages. There are alternatives to the text editor, which we’ll look at in a moment but for the sake of ease, we’ll be doing our examples in Xed. Before you begin, however, run through the customary update check: sudo apt-get update && sudo apt-get upgrade. STEP 2 There are several text editors we can use to create a Bash script: Xed, Vi, Nano, Vim, GNU Emacs and so on. In the end it all comes down to personal preference. Our…

CHOICES AND LOOPS Let’s bring in another command, CHOICE, along with some nested IF and ELSE statements. Start by creating a new script called mychoice.sh. STEP 1 The mychoice.sh script is beginning to look a lot more complex. What we have here is a list of four choices, with three possible options. The options: Mint, Is, and Awesome will be displayed if the user presses the correct option key. If not, then the menu will reappear, the fourth choice. STEP 2 If you follow the script through you soon get the hang of what’s going on, based on what we’ve already covered. WHILE, IF, and ELSE, with the FI closing loop statement will run through the options and bring you back to the start if you pick the wrong option.…

This section contains the building block of C++, from learning how to compile and execute your first C++ code, through to developing user interaction. There’s a lot to learn with C++, but these tutorials, tips and tricks will lead you in the right direction. C++ is different to the other programming languages in this book, and it’s continually evolving as the applications that require it are forever improving. If you know C++, then you’re well on your way to becoming a much sought-after coder and a vital member of the coding community. Your First C++ Program Compile and Execute Using Comments Variables Did You Know? Data Types Strings C++ Maths User Interaction…

THE IMPORTANCE OF COMMENTING Comments inside code are basically human readable descriptions that detail what the code is doing at that particular point. They don’t sound especially important but code without comments is one of the many frustrating areas of programming, regardless of whether you’re a professional or just starting out. In short, all code should be commented in such a manner as to effectively describe the purpose of a line, section, or individual elements. You should get in to the habit of commenting as much as possible, by imagining that someone who doesn’t know anything about programming can pick up your code and understand what it’s going to do simply by reading your comments. In a professional environment, comments are vital to the success of the code and ultimately,…

THE VALUE OF DATA There are many different data types available for the programmer in C++, such as an integer, floating point, Boolean, character and so on. It’s widely accepted that there are seven basic data types, often called Primitive Built-in Types; however, you can create your own data types should the need ever arise within your code. The seven basic data types are: TYPE COMMAND Integer Integer Floating Point float Character char Boolean bool Double Floating Point double Wide Character wchar_t No Value void These basic types can also be extended using the following modifiers: Long, Short, Signed and Unsigned. Basically this means the modifiers can expand the minimum and maximum range values for each data type. For example, the int data type has a default value range of…

HELLO, DAVE You have already used cout, the standard output stream, throughout our code. Now you’re going to be using cin, the standard input stream, to prompt a user response. STEP 1 Anything that you want the user to input into the program needs to be stored somewhere in the system memory, so it can be retrieved and used. Therefore, any input must first be declared as a variable, so it’s ready to be used by the user. Start by creating a blank C++ file with headers. STEP 2 The data type of the variable must also match the type of input you want from the user. For example, to ask a user their age, you would use an integer like this: #include <iostream> using namespace std; int main ()…

PLAYING WITH PYTHON As with most languages, computer or human, it’s all about remembering and applying the right words to the right situation. You’re not born knowing these words, so you need to learn them. STEP 1 If you’ve closed Python 3 IDLE, re-open it as you did in the previous page. In the Shell, enter the familiar following: print (“Hello”) STEP 2 As predicted, the word Hello appears in the Shell as blue text indicating output from a string. It’s fairly straightforward, and doesn’t require too much explanation. Now try: print (“2+2”) STEP 3 You’ll notice that instead of the number 4, the output is the 2+2 you asked to be printed to the screen. The quotation marks are defining what’s being outputted to the IDLE Shell, to print…

XCODE Apple’s Xcode is primarily designed for users to develop apps for macOS, iOS, tvOS and watchOS applications in Swift or Objective-C, but we can use it for C++ too. STEP 1 Start by opening the App Store on your Mac, Apple Menu > App Store. In the Search box enter Xcode, and press Return. There will be many suggestions filling the App Store window, but it’s first option, Xcode, that you need to click on. STEP 2 Take a moment to browse through the app’s information, including the compatibility to ensure you have the correct version of macOS. Xcode requires macOS 10.12.6 or later to install and work. STEP 3 When you’re ready, click on the Get or cloud icon button which will install the Xcode app. Enter your…

Python is one of the most respected and used programming languages in the world. It’s designed to help beginners get into code, but also has some amazingly powerful features that are utilised by data scientists and engineers around the world. You don’t need to look too far to Python at work. It’s used throughout the Internet, and helps drive some of the biggest projects and companies in a multitude of industries. In this section, we look at what you will need to set up and use Python. These steps into a new learning experience are always the hardest, but we’re here to help. How to Set Up Python in Windows How to Set Up Python in Linux Python on the Pi…

THE POWER OF PI While having a far more powerful coding platform on which to write and test your code is ideal, it’s not often feasible. Most of us are unable to jump into a several hundred-pound investment when we’re starting off and this is where the Raspberry Pi can help out. While having a far more powerful coding platform on which to write and test your code is ideal, it’s not often feasible. Most of us are unable to jump into a several hundred-pound investment when we’re starting off and this is where the Raspberry Pi can help out. The Raspberry Pi is a fantastic piece of modern hardware that has created, or rather re-created, the fascination we once all had about computers, how they work, how to code…

TAKING COMMAND The command line is at the core of Linux and when you program with it, this is called scripting. These are self-contained programs designed to be run in the Terminal. STEP 1 The Terminal is where you begin your journey with Linux, through the command line and thus any scripting from. In Linux Mint, it can be accessed by clicking on the Menu followed by the Terminal icon in the panel, or entering ‘Terminal’ into the search bar. STEP 2 The Terminal will give you access to the Linux Mint Shell, called BASH; this gives you access to the underlying operating system, which is why scripting is such a powerful language to learn and use. Everything in Mint, and Linux as a whole, including the desktop and GUI,…

VARIABLES Just as in every other programming language a Bash script can store and call certain variables from the system, either generic or user created. STEP 1 Let’s start by creating a new script called hello.sh; xed hello.sh. In it enter: #!/bin/bash, then, echo Hello $1. Save the file and exit Xed. Back in the Terminal make the script executable with: chmod +x hello.sh. STEP 2 As the script is now executable, run it with. /hello.sh. Now, as you probably expected a simple ‘Hello’ is displayed in the Terminal. However, if you then issue the command with a variable, it begins to get interesting. For example, try. /hello.sh David. STEP 3 The output now will be Hello David. This is because Bash automatically assigns variables for the user, which are…

EASY AUTOMATION AND HANDY SCRIPTS Are you entering line after line of commands to retrieve system information, find a file or rename a batch of files? A script is a better answer. STEP 1 Let’s start by creating a script to help display the Mint system information; always a handy thing to have. Create a new script called sysinfo.sh and enter the following into Xed, or the text editor of your choice. STEP 2 We’ve included a couple of extra commands in this script. The first is the -e extension for echo, this means it’ll enable echo interpretation of additional instances of a new line, as well as other special characters. The proceeding ‘31;43m’ element enables colour for foreground and background. STEP 3 Each of the sections runs a different…

HELLO, WORLD! It’s traditional in programming for the first code to be entered to output the words ‘Hello, World!’ to the screen. Interestingly, this dates back to 1968 using a language called BCPL. STEP 1 We’re going to use Windows 10 and the excellent IDE Code::Blocks for the rest of the C++ code and tutorials in this book. Begin by launching Code::Blocks. When open, click on File > New > Empty File or press Ctrl+Shift+N on the keyboard. STEP 2 Now you can see a blank screen, with the tab labelled *Untitled1, and the number one in the top left of the main Code::Blocks window. Begin by clicking in the main window, so the cursor is next to the number one, and entering: #include <iostream> STEP 3 At the moment…

THE DECLARATION OF VARIABLES You can declare a C++ variable by using statements within the code. There are several distinct types of variables you can declare. Here’s how it works. STEP 1 Open up a new, blank C++ file and enter the usual code headers: #include <iostream> using namespace std; int main() { } STEP 2 Start simple by creating two variables, a and b, with one having a value of 10 and the other 5. You can use the data type int to declare these variables. Within the curly brackets, enter: int a; int b; a = 10; b = 5; STEP 3 You can build and run the code but it won’t do much, other than store the values 10 and 5 to the integers a and b.…

STRING THEORY There are different ways in which you can create a string of characters, which historically are all carried over from the original C language, and are still supported by C++. STEP 1 To create a string you use the char function. Open a new C++ file and begin with the usual header: #include <iostream> using namespace std; int main () { } STEP 2 It’s easy to confuse a string with an array. Here’s an array, which can be terminated with a null character: #include <iostream> using namespace std; int main () { char greet[8] = {‘W’, ‘e’, ‘l’, ‘c’, ‘o’, ‘m’, ‘e’, ‘\0’}; cout << greet << “\n”; } STEP 3 Build and run the code, and ‘Welcome’ appears on the screen. While this is perfectly fine,…

It’s a long way from creating your fist Python code to controlling a robot on Mars, but it’s not impossible. Every advanced and professional Python coder started with the base fundamentals, tips and fixes mentioned in this section. With these foundation Python concepts, you will be able to advance your skills and branch out into whatever Python project you have in mind. From printing Hello World on the screen, looking into conditions and loops, asking a user for input and reacting to it, to using variables to control your code, this is where your Python skills are forged. Starting Python for the First Time Your First Code Saving and Executing Your Code Executing Code from the Command Line…

EDITING CODE You will eventually reach a point where you have to move on from inputting single lines of code into the Shell. Instead, the IDLE Editor will allow you to save and execute your Python code. STEP 1 First, open the Python IDLE Shell. When it’s up, click on File > New File, this will open a new window with Untitled as its name. This is the Python IDLE Editor, and within it, you can enter the code you need to create your future programs. STEP 2 The IDLE Editor is, for all intents and purposes, a simple text editor with Python features, colour coding and so on. You enter code as you would within the Shell, so taking an example from the previous tutorial, enter: print (“Hello everyone!”)…