Indholdsfortegnelse for Issue 7 i Coding & Programming The Complete Manual

Coding is everywhere. From your TV through to the International Space Station, you’ll find millions of lines of code controlling and delivering the services that we take for granted. Behind all this code are the programmers who develop our digital world, using a multitude of different languages to weave the fabric of the Internet, operating systems, games and modern entertainment. We show you the fundamentals for Python, Linux, Raspberry Pi and C++, four of the most powerful languages in the world that are used by the likes of NASA, Microsoft, Apple and throughout the Internet. You will find ideas, concepts, tutorials, hints and projects that will take you from being a beginner to an advanced programmer able to form your own code. Your programming journey starts here… Master your tech…

C++ SETUPS As most, if not all, operating systems have C++ at their code, it stands to reason that you can learn to program in C++ no matter what OS you’re currently using. ☐ COMPUTER Unless you fancy writing out your C++ code by hand on a sheet of paper (which is something many older coders used to do), then a computer is an absolute must have component. PC users can have any recent Linux distro or Windows OS, Mac users the latest macOS. ☐ AN IDE An IDE is used to enter and execute your C++ code. Many IDEs come with extensions and plugins that help make it work better, or add an extra level of functionality. Often, an IDE will provide enhancements depending on the core OS being…

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…

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,…

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: STEP 2 It’s easy to confuse a string with an array. Here’s an array, which can be terminated with a null character: STEP 3 Build and run the code, and ‘Welcome’ appears on the screen. While this is perfectly fine, it’s not a string. A string is a class, which defines objects that can be represented as a stream of characters and doesn’t need to be terminated like an array. The code can therefore be represented…

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…

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: STEP 3 As…

#COMMENTS! A method used by most programmers for keeping their code readable, is by commenting on certain sections. For example, if a variable is used, the programmer comments on what it’s supposed to do. It’s just good practise. STEP 1 We’ll start by creating a new instance of the IDLE Editor (File > New File), and then create a simple variable and print command: Save the file, and execute the code. STEP 2 Running the code will return the line: The value of A is, 10 into the IDLE Shell window – which is what we expected. Now let’s add some of the types of comments you’d normally see within code: STEP 3 Re-save the code and execute it. You’ll see that the output in the IDLE Shell is still…

FUNKY FUNCTIONS A function is a command that you enter into Python in order to do something. It’s a little piece of self-contained code that takes data, works on it, and then returns the result. STEP 1 It’s not only data that a function works on. Functions can do all manner of useful things in Python, such as sort data, change items from one format to another, and check the length or type of items. Basically, a function is a short word followed by brackets. For example, len(), list(), or type(). STEP 2 A function takes data, usually a variable, works on it depending on what the function is programmed to do, and returns the end value. The data being worked on goes inside the brackets, so if you wanted…

POWERING THE PI The Raspberry Pi OS OS has been powering the Raspberry Pi since its release back in 2013. At its core, Raspberry Pi OS is a Linux operating system, based on the hugely popular Debian flavour of Linux. Mike Thompson and Peter Green created Raspberry Pi OS in 2012, to work on the low-performance ARM CPUs found in the early Pi models. Toward the end of 2014, Raspberry Pi OS was further improved to work on the then new model Pi, the Raspberry Pi 2; utilising the 3.18 Linux kernel while still having Debian 7 (codenamed Wheezy) as the base. Mid-way through 2015, Raspberry Pi OS started using Debian 8 (Jessie) as the base, with kernels 4.1, 4.4, and 4.9. Kernel 4.9 was also used from 2017’s Raspberry…

STEP 1 We’re going to use a utility called SD Card Formatter to erase the SD Card with correct formatting. You can download this app from https://www.sdcard.org/downloads/formatter/eula_windows/index.html. Click the Accept button to start the download of the latest version of the software. Extract the software, and double-click the executable to install and run the app. STEP 2 The Drive letter will be automatically assigned depending on the drive(s) in your PC. Click Refresh if it can’t find your SD Card. Ensure the Quick Format option is selected. Enter a name in the Volume Label field to make it easier to identify the card (we used “SD Card”). STEP 3 We’re going to use an 8GB SD Card to install the operating system on our Raspberry Pi. The card needs to…

LINUX MINT – LINUXMINT.COM By far the most popular Linux distro (distribution) is Linux Mint. Mint began life back in 2006, as an alternative to the then, most popular distro, Ubuntu. Although based on Ubuntu’s Long Term Support build, Linux Mint took a different direction to offer the user a better overall experience. Linux Mint has three main desktop versions available with each new version of the core OS it releases. This may sound confusing at first, but it’s quite simple. Currently, Linux Mint uses the Cinnamon Desktop Environment as its flagship model, although MATE and Xfce models are also available. Cinnamon is a graphically rich desktop environment, while MATE uses less fancy graphics but is more stable on a wider variety of desktop systems and finally Xfce is an…

UEFI BIOS The Unified Extensible Firmware Interface (UEFI) is used to identify hardware and protect a PC during its boot-up process. It replaces the traditional BIOS, but can cause issues when installing Linux. STEP 1 Insert your DVD or USB flash drive into your PC and, if you haven’t already, shutdown Windows. In this instance, we’re using the USB boot media but the process is virtually identical. Start the PC and when prompted press the appropriate keys to enter the BIOS or SETUP; these could be, for example, F2, Del or even F12. STEP 2 There are different versions of a UEFI BIOS, so covering them all would be impossible. What you’re looking for is a section that details the Boot Sequence or Boot Mode. Here you’ll have the option…

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,…

C EVERYTHING Due to both the complexity of the language and its power and performance, C++ is often used to develop games, programs, device drivers, and even entire operating systems. Dating back to 1979, the start of the golden era of home computing, C++, or rather C with Classes, was the brainchild of Danish computer scientist Bjarne Stroustrup, while working on his Ph.D. thesis. Stroustrup’s plan was to further the original C language, which had been widely used since the early seventies. C++ proved to be popular among the developers of the 80s, since it was a much easier environment with which to get to grips, and, more importantly, it was 99% compatible with the original C language. This meant that, beyond the mainstream computing labs, regular people who didn’t…

#INCLUDE <C++ IS ACE!> As you learn the basics of programming, you will begin to understand the structure of a program. The commands may be different, but you will start to see how the code works. C++ Danish student Bjarne Stroustrup invented C++ in 1979, as a part of his Ph.D. thesis. Initially C++ was called C with Classes, which added features to the already popular C programming language while making it a more user-friendly environment. Bjarne Stroustrup, inventor of C++. #INCLUDE The structure of a C++ program can look complex, but once you get familiar with it you’ll begin to see how it flows. Every C++ code begins with a directive, #include <>. The directive instructs the pre-processor to include a section of the standard C++ code. For example:…

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,…

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 11 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: STEP 3 At the moment it doesn’t…

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: 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: 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. To output the contents of the variables, add: The cout << “\n”; part simply places a new line between…

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: STEP 2 While simple, it does get the old maths muscle warmed up. Note that we used a float for the numbers variable. While you can happily use an integer, if you suddenly started to use decimals, you would need to change to a float or a double, depending on the accuracy needed. Run the code and…

PYTHON POWER Ever since the earliest home computers were available, enthusiasts, users and professionals have toiled away until the wee hours, slaving over an overheating heap of circuitry to create something akin to magic. These pioneers of programming carved their way into a new frontier, forging small routines that enabled the letter ‘A’ to scroll across the screen. It may not sound terribly exciting to a generation that’s used to ultra high-definition graphics and open world, multi-player online gaming. However, forty-something years ago it was blindingly brilliant. Naturally these bedroom coders helped form the foundations for every piece of digital technology we use today. Some went on to become chief developers for top software companies, whereas others pushed the available hardware to its limits and founded the billion pound gaming…

WHAT WE’RE USING Thankfully, Python is a multi-platform programming language available for Windows, macOS, Linux, Raspberry Pi and more. If you have one of those systems, then you can easily start using Python. ☐ COMPUTER Obviously you’re going to need a computer in order to learn how to program in Python and to test your code. You can use Windows (from XP onward) on either a 32 or 64-bit processor, an Apple Mac or Linux installed PC. ☐ AN IDE An IDE (Integrated Developer Environment) is used to enter and execute Python code. It enables you to inspect your program code and the values within the code, as well as offering advanced features. There are many different IDEs available, so find the one that works for you and gives the…

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…

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, or 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. STEP…

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…

VARIOUS VARIABLES We’ll be working with the Python 3 IDLE Shell in this tutorial. If you haven’t already, open Python 3 or close down the previous IDLE Shell to clear up any old code. STEP 1 In some programming languages, you’re required to use a dollar sign to denote a string, which is a variable made up of multiple characters, such as a name of a person. In Python this isn’t necessary, so, for example, in the Shell enter: name=”David Hayward” (use your own name, unless you’re also called David Hayward). STEP 2 You can check the type of variable in use by issuing the type () command, placing the name of the variable inside the brackets. In our example, this would be: type (name). Add a new string variable:…

TRUE CONDITIONS Keeping conditions simple, to begin with, makes learning to program a more enjoyable experience. Let’s start then by checking if something is TRUE, then doing something else if it isn’t. STEP 1 Let’s create a new Python program that will ask the user to input a word, then check it to see if it’s a four-letter word or not. Start with File > New File, and begin with the input variable: STEP 2 Now we can create a new variable, then use the len function and pass the word variable through it to get the total number of letters the user has just entered: STEP 3 Now we’ll use an if statement to check if the word_ length variable is equal to four, and print a friendly conformation…

THE POWER OF PI With many different versions across four generations of models, the Raspberry Pi is certainly a busy little board. But while each Pi offers something slightly different, for the newcomer it’s a confusing medley of hardware specifications and model numbers. Which, Raspberry Pi hardware, then is going to be best for you? Naturally, that questions depends greatly on what it is you want to do with your Raspberry Pi. If you have a particular project in mind, such as a home media centre server, then you’d probably opt for the more powerful and hardware-capable model of Raspberry Pi. If you want to setup a wireless security camera project, using the Raspberry Pi as the core hardware, then perhaps the Pi Zero W would be a better fit.…

MINTY INGREDIENTS Here’s what you’ll need to install and run Linux Mint as we work through this book. You have several choices available, so take your time and see which works best for you. SYSTEM REQUIREMENTS The minimum system requirements for Linux Mint are as follows: Obviously the better the system you have, the better and quicker the experience will be. USB INSTALLATION You can install Linux Mint onto your computer via USB or DVD. We’ll look into each a little later on, but if you’re already familiar with the process (or you’re thinking of USB and just gathering the hardware you’ll need), then you’re going to need a minimum 4GB USB flash drive/stick to contain the Linux Mint ISO. DVD INSTALLATION DVD installation of Linux Mint simply requires a…

GOING VIRTUAL Using a Virtual Machine (VM) will take resources from your computer: memory, hard drive space, processor usage and so on. So make sure you’ve got enough of each before commencing. STEP 1 We’re using VirtualBox in this instance, as it’s one of the easiest virtual environments to get to grips with. Enter www.virtualbox.org and click on ‘Download VirtualBox’. This will take you to the main download page. Locate the correct host for your system: Windows or Mac – the Host is the current installed operating system and click the link to begin the download. STEP 2 Next, while still at the VirtualBox download page, locate the VirtualBox Extension Pack link. The Extension Pack supports USB devices, as well as numerous other extras that can help make the VM…

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…

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…

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…

X=MISTAKE, PRINT Y There are many pitfalls for the programmer to be aware of, far too many to be listed here. Being able to recognise a mistake and fix it is when you start to move into more advanced territory. SMALL CHUNKS It would be wonderful to be able to work like Neo from The Matrix movies. Simply ask, your operator loads it into your memory and you instantly know everything about the subject. Sadly though, we can’t do that. The first major pitfall is someone trying to learn too much, too quickly. So take coding in small pieces and take your time. EASY VARIABLES Meaningful naming for variables is a must to eliminate common coding mistakes. Having letters of the alphabet is fine but what happens when the code…

“It’s up to you how far to take your coding adventure!” MORE THAN CODE For those of you old enough to remember the ‘80s, the golden era of home computing, the world of computing was a very different scene to how it is today. 8-bit computers that you could purchase as a whole, as opposed to being in kit form and you having to solder the parts together, were the stuff of dreams; and getting your hands on one was sheer bliss contained within a large plastic box. However, it wasn’t so much the new technology that computers then offered, moreover it was the fact that for the first time ever, you could control what was being viewed on the ‘television’. Instead of simply playing one of the thousands of…

Coding can be one of those experiences that sounds fantastic, but is often confusing to tackle. After all, there’s a plethora of languages to choose from, countless apps that will enable you to code in a specific, or range, of languages and an equally huge amount of third-party software to consider. In addition, by accessing the Internet, you will discover that there are countless coding tutorials available for the language in which you’ve decided you want to program, alongside even more examples of code. It’s all a little too much at first. The trick is to slow down and, to begin with, not look too deeply into coding. Like all good projects, you need a solid foundation on which to build your skillset and to have all the necessary tools…

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.…

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…

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: 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 - 2147483648 to 2147483647, a fair value, you would agree. Now, if you were to use one of the modifiers, the…

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: STEP 3 The cin command works in the…

Python’s ability to create highly readable code, within a small set of instructions, has a considerable impact on our modern digital world. From being an ideal first programmers’ choice through to being able to create interactive stories and games; from scientific applications through to artificial Intelligence and web-based applications, the only limit to Python is the imagination of the person coding in it. It’s Python’s malleable design that makes it an ideal language for many different situations and roles. Even certain aspects of the coding world that require more efficient code still use Python. For example, NASA utilises Python both as a stand-alone language and as a bridge between other programming languages. This way, NASA scientists and engineers are able to get to the data they need without having to…

The Python Software Foundation, a non-profit organisation devoted to both furthering and improving Python, currently develops the language. The foundation’s purpose is to “promote, protect, and advance the Python programming language, and to support and facilitate the growth of a diverse and international community of Python programmers.” The structure of Python code has been designed to flow easily, allowing those who are just beginning to code to follow it without too much difficulty. Yet, despite its ease of use, Python is regularly used throughout a number of industries in real-world scenarios. Big Data and AI are the two fastest growing Python-backed technologies at the moment. Big Data is simply a modern term used to describe huge amounts of data, such as sequences of numbers collated during a day’s worth of…

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. 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 and foundation level electronics. Thanks to its unique mix of hardware and custom software, it has proved itself to be an amazing platform on which to learn how to code; specifically, using Python. While you’re able, with ease, to use the Raspberry Pi to learn to code with…

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: 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: 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 the total of 2+2…

IT’S ALL MATHS, MAN You can get some really impressive results from the mathematical powers of Python, as maths is the driving force behind the code with most, if not all, programming languages. STEP 1 Open up the GUI version of Python 3, as mentioned you can use either the Shell or the Editor. For the time being, we’re going to use the Shell. If you’ve opted to use a third-party text editor, note that you need to get to the IDLE Shell for this part of the tutorial. STEP 2 In the Shell enter the following: As you can see, Python can handle some quite large numbers. STEP 3 You can use all the customary Mathematical operations: divide, multiply, brackets and so on. Practise with a few, for example:…

USER FRIENDLY The type of input you want from the user will depend greatly on the type of program you’re coding. A game, for example, may ask for a character’s name, whereas a database can ask for personal details. STEP 1 If it’s not already, open the Python 3 IDLE Shell, and start a New File in the Editor. Let’s begin with something really simple, enter: STEP 2 Save and execute the code, and, as you no doubt suspected, in the IDLE Shell the program will ask for your first name, storing it as the variable firstname, followed by your surname; also stored in its own variable (surname). STEP 3 we want: Now that we have the user’s name stored in a couple of variables, we can call them up…

MASTERING MODULES Think of modules as an extension that’s imported into your Python code to enhance and extend its capabilities. There are countless modules available, and as we’ve seen, you can even make your own. STEP 1 Although good, the built-in functions within Python are limited. The use of modules, however, allows us to make more sophisticated programs. As you are aware, modules are Python scripts that are imported, such as import math. STEP 2 Some modules, especially on the Raspberry Pi, are included by default; the Math module is a prime example. Sadly, other modules aren’t always available. A good example on non-Pi platforms is the Pygame module, which contains many functions to help create games. Try: import pygame. STEP 3 The result is an error in the IDLE…

STEP 1 The most important thing you need is an SD Card. These are the storage cards commonly found in digital cameras. All modern Raspberry Pi boards, including the Raspberry Pi 3 and Pi Zero, use Micro SD cards but the older boards may use a larger SD Card. STEP 2 You’ll need a HDMI cable to connect your Raspberry Pi to a monitor or television set; these cables are used with modern televisions and video game consoles, so you shouldn’t find it too hard to pick up a spare. If you own a Pi Zero, or you’ve got a Pi 4, you’ll need a micro-HDMI cable in order to connect to a monitor or TV. STEP 3 The SD Card plugs into the SD Card socket. On the Raspberry…

FREE AND OPEN Linux is a fantastic fit for those who want something different; the efficiency of the system, the availability of applications and its stability, are just a few reasons why. The first thing we need to address is that there is no basic operating system called Linux. Fundamentally, Linux is the operating system kernel, the core component of an OS. When talking about Linux we are, in fact, referring to one of the many distributions, or distros, that use the Linux kernel. No doubt you’ve heard of at least one of the current popular distros: Ubuntu, Linux Mint, Fedora, openSUSE, Debian, Raspberry Pi OS… the list goes on. Each one of these distros offers the user something a little different. While each has the Linux kernel at its…

DVD BOOTABLE MEDIA We’re using a Windows 11 PC here to transfer the ISO to a DVD. As long as you’re using a version of Windows from 7 onward, the process is extremely easy. STEP 1 First locate the ISO image of Linux you’ve already downloaded. In Windows 7, 8.1 and 10 computers, you’ll usually find this in the Downloads folder unless, when saving it, you’ve specified a different location. STEP 2 Next, insert a recordable DVD disc into your computer’s optical drive. After a few seconds, while the disc is read, Windows will display a pop-up message asking you what to do with the newly inserted disc, ignore this as we’re going to use the built-in image burning function. STEP 3 Right-click the Linux ISO and from the menu…

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…

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…

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.…

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…

DEF BEGINNER(MISTAKES=10) Here are ten common Python programming mistakes most beginners find themselves making. Being able to identify these mistakes will save you headaches in the future. VERSIONS To add to the confusion that most beginners already face when coming into programming, Python has two live versions of its language available to download and use. There is Python version 2.7.x and Python 3.6.x. The 3.6.x version is the most recent, and the one we’d recommend starting. But, version 2.7.x code doesn’t always work with 3.6.x code and vice versa. THE INTERNET Every programmer has and does at some point go on the Internet and copy some code to insert into their own routines. There’s nothing wrong with using others’ code, but you need to know how the code works and…

VOID(C++, MISTAKES) Admittedly it’s not just C++ beginners that make the kinds of errors we outline on these pages, even hardened coders are prone to the odd mishap here and there. Here are some common issues to try and avoid. UNDECLARED IDENTIFIERS A common C++ mistake, and to be honest a common mistake with most programming languages, is when you try and output a variable that doesn’t exist. Displaying the value of x on-screen is fine but not if you haven’t told the compiler what the value of x is to begin with. SEMICOLONS Remember that each line of a C++ program must end with a semicolon. If it doesn’t then the compiler treats the line with the missing semicolon as the same line with the next semicolon on. This…