codemistic.github.io/cpp/variables-and-literals.html at master · codemistic/codemistic.github.io

602 lines (519 loc) · 27.6 KB
<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="In programming, a variable is a container (storage area) to hold data." />
    <meta name="keywords"
        content="variables, literals, variables in cpp, variables in c++, literals in c++, literals in cpp, variables and literals, variables and literals in cpp, variables and literals in c++, c++, cpp" />
    <title>C++ Variables and Literals | C++ Tutorials | CodeMistic</title>
    <!-- Google Ad -->
    <script data-ad-client="ca-pub-5352867889640158" async
        src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
    <!-- Google Tag Manager -->
    <script>(function (w, d, s, l, i) {
            w[l] = w[l] || []; w[l].push({
                'gtm.start':
                    new Date().getTime(), event: 'gtm.js'
            }); var f = d.getElementsByTagName(s)[0],
                j = d.createElement(s), dl = l != 'dataLayer' ? '&l=' + l : ''; j.async = true; j.src =
                    'https://www.googletagmanager.com/gtm.js?id=' + i + dl; f.parentNode.insertBefore(j, f);
        })(window, document, 'script', 'dataLayer', 'GTM-MCNC43J');</script>
    <!-- End Google Tag Manager -->
    <!-- Global site tag (gtag.js) - Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-YPTQSLH0XW"></script>
    <script>
        window.dataLayer = window.dataLayer || [];
        function gtag() { dataLayer.push(arguments); }
        gtag('js', new Date());
        gtag('config', 'G-YPTQSLH0XW');
    </script>
    <!-- Favicon -->
    <link rel="icon" type="img/png" href="../favicon.png" />
    <!-- FONT AWESOME -->
    <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.13.1/css/all.css"
        integrity="sha384-xxzQGERXS00kBmZW/6qxqJPyxW3UR0BPsL4c8ILaIWXva5kFi7TxkIIaMiKtqV1Q" crossorigin="anonymous" />
    <!-- FONTS -->
    <link href="https://fonts.googleapis.com/css2?family=Kalam:wght@700&family=Ubuntu&family=Varela+Round&display=swap"
        rel="stylesheet" />
    <!-- Animate on scroll -->
    <link rel="stylesheet" href="https://unpkg.com/aos@next/dist/aos.css" />
    <!-- Bootstrap -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css"
        integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous" />
    <!-- CSS -->
    <link rel="stylesheet" href="../lang_styles.css" />
    <!-- Google Tag Manager (noscript) -->
    <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MCNC43J" height="0" width="0"
            style="display:none;visibility:hidden"></iframe></noscript>
    <!-- End Google Tag Manager (noscript) -->
    <!-- NAVIGATION BAR -->
    <!-- <div class="container-fluid"> -->
    <nav class="navbar fixed-top navbar-expand-xl navbar-dark">
        <a class="navbar-brand" href="../index.html">CODEMISTIC</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarSupportedContent">
            <ul class="navbar-nav ml-auto">
                <li class="nav-item">
                    <a class="nav-link" href="../index.html">Home</a>
                </li>
                <li class="nav-item dropdown">
                    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button"
                        data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        Tutorials
                    <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                        <a class="dropdown-item" href="../cpp.html">C++</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="../python.html">Python</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="../java.html">Java</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="../dsa.html">Data Structure and Algorithms</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="../tutorials.html">All Tutorials</a>
                    </div>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="../events.html">Events</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="../teen-code.html">Teen-Code</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="../campus.html">Campus Programme</a>
                </li>
                <!-- <li class="nav-item">
                        <a class="nav-link" href="https://docs.google.com/forms/d/e/1FAIpQLSc2O28YJpxQc6kh2tKpI_Lf5MwfwGXVnhMs0g5EEXobJ4Beeg/viewform?usp=sf_link" target="_blank">Contribute</a>
                    </li> -->
                <li class="nav-item">
                    <a class="nav-link" href="../register.html">Join Our Community</a>
                </li>
            </ul>
        </div>
    <!-- Accordion -->
    <section class="lbar">
        <div class="lang-img col-md-2">
            <img src="../logo/cpp.png" alt="c++" class="cpp-img" style="margin-left: -25px;">
        </div>
        <ul id="accordion" class="accordion ml-5">
            <li class=" collape in">
                <div class="link">C++ Introduction<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse show">
                        <a href="getting-started.html" class="closed">Getting Started</a>
                        <a href="variables-and-literals.html " class="opened">C++ Variables and Literals</a>
                        <a href="data-types.html" class="closed">C++ Data Types</a>
                        <a href="input-output.html" class="closed">C++ Basic I/O</a>
                        <a href="type-conversion.html" class="closed">C++ Type Conversion</a>
                        <a href="operators.html" class="closed">C++ Operators</a>
                        <a href="comments.html" class="closed">C++ Comments</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Flow Control<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="if-else.html" class="closed">C++ if...else</a>
                        <a href="for-loop.html" class="closed">C++ for Loop</a>
                        <a href="do-while.html" class="closed">C++ do...while Loop</a>
                        <a href="break-and-continue.html" class="closed">C++ break & continue</a>
                        <a href="switch-statement.html" class="closed">C++ switch Statement</a>
                        <a href="goto-statement.html" class="closed">C++ goto Statement</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Function<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="functions.html" class="closed">C++ Functions</a>
                        <a href="function-types.html" class="closed">C++ Function Types</a>
                        <a href="function-overloading.html" class="closed">C++ Function Overloading</a>
                        <a href="default-argument.html" class="closed">C++ Default Argument</a>
                        <a href="storage-class.html" class="closed">C++ Storage Class</a>
                        <a href="recursion.html" class="closed">C++ Recursion</a>
                        <a href="return-reference.html" class="closed">C++ Return Reference</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Arrays & String<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="arrays.html" class="closed">C++ Arrays</a>
                        <a href="multidimensional-arrays.html" class="closed">C++ Multidimensional Arrays</a>
                        <a href="function-arrays.html" class="closed">C++ Function and Array</a>
                        <a href="string.html" class="closed">C++ String</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Structures<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="structures.html" class="closed">C++ Structures</a>
                        <a href="structure-fuction.html" class="closed">Structure and Function</a>
                        <a href="pointers-structures.html" class="closed">C++ Pointers to Structure</a>
                        <a href="enumeration.html" class="closed">C++ Enumeration</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Object & Class<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="object-class.html" class="closed">C++ Objects and Class</a>
                        <a href="constructors.html" class="closed">C++ Constructors</a>
                        <a href="objects-fuctions.html" class="closed">C++ Objects & Function</a>
                        <a href="operator-overloading.html" class="closed">C++ Operator Overloading</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Pointers<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="pointers.html" class="closed">C++ Pointers</a>
                        <a href="pointers-arrays.html" class="closed">C++ Pointers and Arrays</a>
                        <a href="pointers-functions.html" class="closed">C++ Pointers and Functions</a>
                        <a href="memory-management.html" class="closed">C++ Memory Management</a>
                </ul>
            </li>
            <li>
                <div class="link">C++ Inheritance<i class="fa fa-chevron-down"></i>
                </div>
                <ul class="submenu collapse">
                        <a href="inheritance.html" class="closed">C++ Inheritance</a>
                        <a href="inheritance-access-control.html" class="closed">Inheritance Access Control</a>
                        <a href="function-overriding.html" class="closed">C++ Function Overriding</a>
                        <a href="inheritence-types.html" class="closed">Inheritance Types</a>
                        <a href="friend-function.html" class="closed">C++ Friend Function</a>
                        <a href="virtual-function.html" class="closed">C++ Virtual Function</a>
                        <a href="templates.html" class="closed">C++ Templates</a>
                </ul>
            </li>
        </ul>
    </section>
    <section class="para">
        <!-- <div class="but mt-4">
            &nbsp;&nbsp;&nbsp;&nbsp;<button class="btn btn-md btn-primary "><a href="../dsa.html"><i
                        class="fas fa-arrow-left "></i>&nbsp;Back to Index</a></button>
        </div> -->
        <!-- breadcrumb -->
        <nav class="bdcrumb" id="bdcrumb" aria-label="breadcrumb">
            <ul class="breadcrumb">
                <li class="breadcrumb-item"><a href="../tutorials.html"><i class="fas fa-home"></i></a></li>
                <li class="breadcrumb-item"><a href="../cpp.html">C++ Tutorials</a></li>
                <li class="breadcrumb-item active" aria-current="page">C++ Variables and Literals</li>
            </ul>
        </nav>
        <!-- breadcrumb ending -->
        <!-- HEADING -->
        <div class="wrapper">
            <h3 class="pb-3 pt-3">C++ Variables, Literals and Constants</h3>
            <p>In this tutorial, we will learn about variables, literals, and constants in C++ with the
                help of examples.</p>
            <h4 class="pb-3 pt-3">C++ Variables</h4>
            <p>In programming, a variable is a container (storage area) to hold data.</p>
            <p>To indicate the storage area, each variable should be given a unique name (identifier). For
                example:</p>
            <pre>int age = 38;</pre>
            </p>
            <p>Here, age is a variable of the <code>int</code> data type, and we have assigned an integer value
                <code>38</code> to it.</p>
            <p><strong>Note : </strong> The <code>int</code> data type suggests that the variable can only hold
                integers. Similarly, we can use the <code>double</code> data type if we have to store decimals and
                exponentials.</p>
            <p>We will learn about all the data types in detail in the next tutorial.</p>
            <p>The value of a variable can be changed, hence the name variable.</p>
            <pre>int age = 38; // age is 38
age = 44; // age is 44</pre>
            </p>
            <h5 class="pb-3 pt-3">Rules for naming a variable</h5>
            <ol type="1">
                <li>A variable name can only have alphabets, numbers and the underscore.</li>
                <li>A variable name cannot begin with a number.</li>
                <li>Variable names cannot begin with a number.</li>
                <li>A variable name cannot be a keyword. For example, <code>int</code> is a keyword that is used to
                    denote variables.</li>
                <li>A variable name can start with an underscore. However, it's not considered a good practice.</li>
            </ol>
            <p><strong>Note : </strong>We should try to give meaningful names to variables. For
                example, <code>first_name</code> is a better variable name than fn.</p>
            <hr>
            <h3 class="pb-3 pt-3">C++ Literals</h3>
            <p>Literals are data used for representing fixed values. They can be used directly in the code. For example: <code>1</code>, <code>2.5</code>, <code>'c'</code> etc.</p>
            <p>Here, <code>1</code>, <code>2.5</code>, <code>'c'</code> are literals. Why? You cannot assign different values to these terms.</p>
            <p>Here's a list of different literals in C++ programming.</p>
            <h3 class="pb-3 pt-3">1. Integers</h3>
            <p>An integer is a numeric literal(associated with numbers) without any fractional or exponential part. There are three types of integer literals in C programming:</p>
            <ul>
                <li>Becimal (base 10)</li>
                <li>Octal (base 8)</li>
                <li>Hexadecimal (base 16)</li>
            </ul>
            <p>For example:</p>
            <pre>Decimal: 0, -9, 22, etc.
Octal: 021, 077, 033, etc.
Hexadecimal: 0x7f, 0x2a, 0x521, etc.</pre>
            <p>In C++ programming, octal starts with a 0, and hexadecimal starts with a <code>0x</code>.</p>
            <h4 class="pb-3 pt-3">2. Floating-point Literals</h4>
            <p>A floating-point literal is a numeric literal that has either a fractional form or an exponent form. For example: <code>-2.0</code>, <code>0.0000234</code>, <code>-0.22e-5</code></p>
            <p><strong>Node : </strong><code>e-5 = 10<sup>-5</sup></code></p>
            <h4 class="pb-3 pt-3">3. Characters</h4>
            <p>A character literal is created by enclosing a single character inside single quotation marks.
                For example: <code>'a'</code>, <code>'m'</code>, <code>'F'</code>, <code>'2'</code>, <code>'}'</code>, etc.</p>
            <h4 class="pb-3 pt-3">4. Escape sequences</h4>
            <p>Sometimes, it is necessary to use characters that cannot be typed or has special meaning in C++ programming. For example, newline (enter), tab, question mark, etc.</p>
            <p>In order to use these characters, escape sequences are used.</p>
            <table class="content m-2">
                <thead>
                    <th>Escape sequence</th>
                    <th>Character</th>
                </thead>
                <tbody>
                        <td style="text-align: center;"><code>\b</code></td>
                        <td>Backspace</td>
                        <td style="text-align: center;"><code>\f</code></td>
                        <td>Form feed</td>
                        <td style="text-align: center;"><code>\n</code></td>
                        <td>Newline</td>
                        <td style="text-align: center;"><code>\r</code></td>
                        <td>Return</td>
                        <td style="text-align: center;"><code>\t</code></td>
                        <td>Horizontal tab</td>
                        <td style="text-align: center;"><code>\v</code></td>
                        <td>Vertical tab</td>
                        <td style="text-align: center;"><code>\\</code></td>
                        <td>Backslash</td>
                        <td style="text-align: center;"><code>\'</code></td>
                        <td>Single quotation mark</td>
                        <td style="text-align: center;"><code>\\"</code></td>
                        <td>Double quotation mark</td>
                        <td style="text-align: center;"><code>\?</code></td>
                        <td>Question mark</td>
                        <td style="text-align: center;"><code>\0</code></td>
                        <td>Null character</td>
                </tbody>
            </table>
            <h4 class="pb-3 pt-3">5. String Literals</h4>
            <p>A string literal is a sequence of characters enclosed in double-quote marks. For example:</p>
            <table class="content m-2">
                    <td style="text-align: center;"><code>"good"</code></td>
                    <td>String constant</td>
                </tr>
                    <td style="text-align: center;"><code>""</code></td>
                    <td>Null string constant</td>
                </tr>
                    <td style="text-align: center;"><code>" "</code></td>
                    <td>string constant of white space</td>
                </tr>
                    <td style="text-align: center;"><code>"Earth is round.\n"</code></td>
                    <td>Prints string with a newline</td>
                </tr>
            </table>
            <p>We will learn about strings in detail in the C++ string tutorial.</p>
            <hr>
            <h3 class="pb-3 pt-3">C++ Constants</h3>
            <p>In C++, we can create variables whose value cannot be changed. For that, we use the <code>const</code> keyword. Here's an example:</p>
            <pre>const int LIGHT_SPEED = 299792458;
LIGHT_SPEED = 2500 // Error! LIGHT_SPEED is a constant.</pre>
            <p>Here, we have used the keyword const to declare a constant named <code>LIGHT_SPEED</code>. If we try to change the value of <code>LIGHT_SPEED</code>, we will get an error.</p>
            <p>A constant can also be created using the <code>#define</code> preprocessor directive. We will learn about it in detail in the C++ Macros tutorial.</p>
        </div>
        <div class="but text-right">
            <button class="btn btn-primary pull-right"><a href="data-types.html">Next Topic&nbsp;<i
                        class="fas fa-arrow-right "></i><br />C++ Data Types</a></button>
        </div><br />
    </section>
    <!-- footer -->
    <footer>
        <div class="row footer">
            <div class="logo">
                <img src="../image.png" alt="" class="f-img">
                <h5>LEARN CODE DISCUSS</h5>
            </div>
            <div class="footer-column ">
                <ul class="footer-ul">
                    <li class="foot-header"><strong>CodeMistic</strong></li>
                    <li class="f-li"><a href="../index.html" class="f-links">Home</a></li>
                    <li class="f-li"><a href="../team.html" class="f-links">Our Team</a></li>
                    <li class="f-li"><a href="../terms-and-conditions.html" class="f-links">Terms of Service</a></li>
                    <li class="f-li"><a href="../privacy-policy.html" class="f-links">Privacy Policy</a></li>
                </ul>
            </div>
            <div class="footer-column ">
                <ul class="footer-ul ">
                    <li class="foot-header"><strong>LEARN</strong></li>
                    <li class="f-li"><a href="../cpp.html" class="f-links">C++</a></li>
                    <li class="f-li"><a href="../java.html" class="f-links">Java</a></li>
                    <li class="f-li"><a href="../python.html" class="f-links">Python</a></li>
                    <li class="f-li"><a href="../dsa.html" class="f-links">DSA</a></li>
                </ul>
            </div>
            <div class="footer-column ">
                <ul class="footer-ul ">
                    <li class="foot-header"><strong>CONTRIBUTE</strong></li>
                    <li class="f-li"><a
                            href="https://docs.google.com/forms/d/e/1FAIpQLSduxk_aP9M1lqUAebQJwRXiVm2ukmdgv3T7gjBpOsr_gdeOcQ/viewform?usp=sf_link"
                            class="f-links" target="_blank">Write an Article/Blog</a></li>
                    <li class="f-li"><a
                            href="https://docs.google.com/forms/d/e/1FAIpQLSc2O28YJpxQc6kh2tKpI_Lf5MwfwGXVnhMs0g5EEXobJ4Beeg/viewform?usp=sf_link"
                            class="f-links" target="_blank">Internships</a></li>
                    <li class="f-li"><a
                            href="https://docs.google.com/forms/d/e/1FAIpQLSe9nr_Aw0fGIqm3_xWhqEzTr3UWdOFz-pvKpQvkAsosORYq9w/viewform?usp=sf_link"
                            class="f-links" target="_blank">Videos</a></li>
                    <li class="f-li"><a
                            href="https://docs.google.com/forms/d/e/1FAIpQLScOW3hJjxxwzPYL4u51oboc4T1aDtIUEIRa20hKPKu4UlcZAA/viewform?usp=sf_link"
                            class="f-links" target="_blank">Donations/Funds</a></li>
                </ul>
            </div>
        </div>
        <div class="footer-links" style="text-align: center;">
            <!-- <h7>Connect With Us</h7><br><br> -->
            <a href="https://www.facebook.com/codemistic " target="_blank "><i class="icons fa-2x fab fa-facebook "
                    style="color:#3b5998; "></i></a>
            <a href="https://www.instagram.com/codemistic " target="_blank "><i class="icons fa-2x fab fa-instagram "
                    style="color:#e95950; "></i></a>
            <a href="https://www.twitter.com/codemistic " target="_blank "><i class="icons fa-2x fab fa-twitter "
                    style="color:#8accf5; "></i></a>
            <a href="https://www.linkedin.com/company/codemistic " target="_blank "><i
                    class="icons fa-2x fab fa-linkedin " style="color:#88b3ee; "></i></a>
            <a href="https://t.me/codemistic " target="_blank "><i class="icons fa-2x fab fa-telegram "
                    style="color:#65adda; "></i></a>
            <a href="https://www.youtube.com/channel/UCS1Iv_kkgQGDwoXtvrlwlag " target="_blank "><i
                    class="icons fa-2x fab fa-youtube " style="color:red; "></i></a>
            <p class="foot mt-3">&#169 Copyright : <strong>CodeMistic</strong> All Rights Reserved.</p>
        </div>
    </footer>
    <!-- CSS Scripts -->
    <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js "
        integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj "
        crossorigin="anonymous "></script>
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js "
        integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo "
        crossorigin="anonymous "></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js "
        integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI "
        crossorigin="anonymous "></script>
    <script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>
    <script src='../side.js'></script>
Provide feedback

Saved searches

Use saved searches to filter your results more quickly

FilesExpand file tree

variables-and-literals.html

Latest commit

History

variables-and-literals.html

File metadata and controls
