Programming in C: Practice Questions and Answers for Unit

Note: Practice coding of HTML, CSS, XML and WML along with following questions answers.

Q. What is Internet?

A. The Internet is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1970s.

Q. Explain Basic internet protocols?

A. In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. Different protocols often describe different aspects of a single communication; taken together, these form a protocol stack. The terms "protocol" and "protocol stack" also refer to the software that implements a protocol. Common Internet protocols include TCP/IP (Transmission Control Protocol/Internet Protocol), UDP/IP (User Datagram Protocol/Internet Protocol), HTTP (HyperText Transfer Protocol) and FTP (File Transfer Protocol).

TCP/IP: TCP/IP is a stream protocol. This means that a connection is negotiated between a client and a server. Any data transmitted between these two endpoints is guaranteed to arrive, thus it is a so-called lossless protocol. Since the TCP protocol (as it is also referred to in short form) can only connect two endpoints, it is also called a peer-to-peer protocol.
HTTP: HTTP is the protocol used to transmit all data present on the World Wide Web. This includes text, multimedia and graphics. It is the protocol used to transmit HTML, the language that makes all the fancy decorations in your browser. It works upon TCP/IP.
FTP: FTP is the protocol used to transmit files between computers connected to each other by a TCP/IP network, such as the Internet.

Q. What is World Wide Web?

A. World Wide Web, which is also known as a Web, is a collection of websites or web pages stored in web servers and connected to local computers through the internet. These websites contain text pages, digital images, audios, videos, etc. Users can access the content of these sites from any part of the world over the internet using their devices such as computers, laptops, cell phones, etc. Multiple web resources with a common theme and usually a common domain name make up a website. Websites are stored in computers that are running a web server, which is a program that responds to requests made over the Internet from web browsers running on a user's computer. Website content can be provided by a publisher or interactively from user-generated content. Websites are provided for a myriad of informative, entertainment, commercial, and governmental reasons.

Q. What is Hypertext Transfer Protocol(HTTP)?

A. HTTP stands for HyperText Transfer Protocol. It is a protocol used to access the data on the World Wide Web (www). The HTTP protocol can be used to transfer the data in the form of plain text, hypertext, audio, video, and so on. This protocol is known as HyperText Transfer Protocol because of its efficiency that allows us to use in a hypertext environment where there are rapid jumps from one document to another document.

Features of HTTP:

Connectionless protocol: HTTP is a connectionless protocol. HTTP client initiates a request and waits for a response from the server. When the server receives the request, the server processes the request and sends back the response to the HTTP client after which the client disconnects the connection. The connection between client and server exist only during the current request and response time only.
Media independent: HTTP protocol is a media independent as data can be sent as long as both the client and server know how to handle the data content. It is required for both the client and server to specify the content type in MIME-type header.
Stateless: HTTP is a stateless protocol as both the client and server know each other only during the current request. Due to this nature of the protocol, both the client and server do not retain the information between various requests of the web pages.

Q. What is URL?

A. URL is Uniform Resource Locator. A client that wants to access the document in an internet needs an address and to facilitate the access of documents, the HTTP uses the concept of Uniform Resource Locator (URL). The Uniform Resource Locator (URL) is a standard way of specifying any kind of information on the internet.

The URL defines four parts: method, host computer, port, and path.

method: // host computer : port/path.

http: //www.example.com: 2345/index.html

Method: The method is the protocol used to retrieve the document from a server. For example, HTTP.
Host: The host is the computer where the information is stored, and the computer is given an alias name. Web pages are mainly stored in the computers and the computers are given an alias name that begins with the characters "www". This field is not mandatory.
Port: The URL can also contain the port number of the server, but it's an optional field. If the port number is included, then it must come between the host and path and it should be separated from the host by a colon.
Path: Path is the pathname of the file where the information is stored. The path itself contain slashes that separate the directories from the subdirectories and files.

Q. What is XHTML?

A. Extensible HyperText Markup Language (XHTML) is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated. XHTML was developed to make HTML more extensible and increase interoperability with other data formats. In addition, browsers were forgiving of errors in HTML, and most websites were displayed despite technical errors in the markup; XHTML introduced stricter error handling. XHTML is an application of XML. XHTML documents are well-formed and may therefore be parsed using standard XML parsers, unlike HTML, which requires a lenient HTML-specific parser. XHTML 1.0 became a World Wide Web Consortium (W3C) recommendation on 26 January 2000. XHTML 1.1 became a W3C recommendation on 31 May 2001. The standard known as XHTML5 is being developed as an XML adaptation of the HTML5 specification.

Q. What is HTML?

A. The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript. Web browsers receive HTML documents from a web server or from local storage and render the documents into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for the appearance of the document.

HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects such as interactive forms may be embedded into the rendered page. HTML provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. HTML elements are delineated by tags, written using angle brackets. Tags such as <img /> and <input /> directly introduce content into the page. Other tags such as <p> surround and provide information about document text and may include other tags as sub-elements. Browsers do not display the HTML tags but use them to interpret the content of the page. HTML can embed programs written in a scripting language such as JavaScript, which affects the behavior and content of web pages. Inclusion of CSS defines the look and layout of content.

Q. What are HTML tags?

Defines a comment
<!DOCTYPE> Defines the document type
<a> Defines a hyperlink
<area> Defines an area inside an image map
<b> Defines bold text
<body> Defines the document's body
<br> Defines a single line break
<center> Not supported in HTML5. Use CSS instead.
<div> Defines a section in a document
<font> Not supported in HTML5. Use CSS instead.
<form> Defines an HTML form for user input
<h1> to <h6> Defines HTML headings
<head> Contains metadata/information for the document
<hr> Defines a thematic change in the content
<html> Defines the root of an HTML document
<img> Defines an image
<input> Defines an input control
<li> Defines a list item
<link> Defines the relationship between a document and an external resource (most used to link to style sheets)
<map> Defines an image map
<meta> Defines metadata about an HTML document
<ol> Defines an ordered list
<option> Defines an option in a drop-down list
<p> Defines a paragraph
<pre> Defines preformatted text
<script> Defines a client-side script
<select> Defines a drop-down list
<span> Defines a section in a document
<strong> Defines important text
<style> Defines style information for a document
<table> Defines a table
<tr> Defines a row in a table
<th> Defines a header cell in a table
<tbody> Groups the body content in a table
<td> Defines a cell in a table
<textarea> Defines a multiline input control (text area)
<title> Defines a title for the document
<ul> Defines an unordered list

Q. What is CSS style sheets?

A. Cascading Style Sheets (CSS) is used to format the layout of a webpage. With CSS, you can control the color, font, the size of text, the spacing between elements, how elements are positioned and laid out, what background images or background colors are to be used, different displays for different devices and screen sizes.

CSS can be added to HTML documents in 3 ways:

Inline - by using the style attribute inside HTML elements
Internal - by using a <style> element in the <head> section
External - by using a <link> element to link to an external CSS file

The most common way to add CSS, is to keep the styles in external CSS files. However, in this tutorial we will use inline and internal styles, because this is easier to demonstrate, and easier for you to try it yourself.

Inline CSS : An inline CSS is used to apply a unique style to a single HTML element. An inline CSS uses the style attribute of an HTML element. The following example sets the text color of the <h1> element to blue, and the text color of the <p> element to red:

Example - <h1 style="color:blue;">A Blue Heading</h1>

Internal CSS: An internal CSS is used to define a style for a single HTML page. An internal CSS is defined in the <head> section of an HTML page, within a <style> element. The following example sets the text color of ALL the <h1> elements (on that page) to blue, and the text color of ALL the <p> elements to red. In addition, the page will be displayed with a "powderblue" background color:

Example

<!DOCTYPE html>

<html>

<head>

<style>

body {background-color: powderblue;}

h1 {color: blue;}

p {color: red;}

</style>

</head>

<body>

<h1>This is a heading</h1>

<p>This is a paragraph.</p>

</body>

</html>

External CSS

An external style sheet is used to define the style for many HTML pages. To use an external style sheet, add a link to it in the <head> section of each HTML page:

Example

<!DOCTYPE html>

<html>

<head>

</head>

<body>

<h1>This is a heading</h1>

<p>This is a paragraph.</p>

</body>

</html>

The external style sheet can be written in any text editor. The file must not contain any HTML code, and must be saved with a .css extension.

Here is what the "styles.css" file looks like:

"styles.css":

body {

background-color: powderblue;

}

h1 {

color: blue;

}

p {

color: red;

}

Q. What is CSS box model?

A. In CSS, the term "box model" is used when talking about design and layout. The CSS box model is essentially a box that wraps around every HTML element. It consists of: margins, borders, padding, and the actual content. The image below illustrates the box model:

Explanation of the different parts:

Content - The content of the box, where text and images appear
Padding - Clears an area around the content. The padding is transparent
Border - A border that goes around the padding and content
Margin - Clears an area outside the border. The margin is transparent

The box model allows us to add a border around elements, and to define space between elements.

Example

Demonstration of the box model:

div {

width: 300px;

border: 15px solid green;

padding: 50px;

margin: 20px;

}

Q. What is DHTML?

A. Dynamic HTML, or DHTML, is a term which was used by some browser vendors to describe the combination of HTML, style sheets and client-side scripts (JavaScript, VBScript, or any other supported scripts) that enabled creation of interactive and animated documents. DHTML allows scripting languages to change variables in a web page's definition language, which in turn affects the look and function of otherwise "static" HTML page content, after the page has been fully loaded and during the viewing process. Thus the dynamic characteristic of DHTML is the way it functions while a page is viewed, not in its ability to generate a unique page with each page load.

Q. What is XML?

A. XML (Extensible Markup Language) is a markup language similar to HTML, but without predefined tags to use. Instead, you define your own tags designed specifically for your needs. This is a powerful way to store data in a format that can be stored, searched, and shared. Most importantly, since the fundamental format of XML is standardized, if you share or transmit XML across systems or platforms, either locally or over the internet, the recipient can still parse the data due to the standardized XML syntax. The whole structure of XML and XML-based languages is built on tags. XML - declaration is not a tag. It is used for the transmission of the meta-data of a document.

<?xml version="1.0" encoding="UTF-8"?>

Example

<?xml version="1.0" encoding="UTF-8"?>

<breakfast_menu>

<food>

<name>Veg Burger</name>

</food>

<food>

<name>Aloo Parantha</name>

</food>

<food>

<name>French Toast</name>

</food>

</breakfast_menu>

Q. What is WML?

A. Wireless Markup Language (WML), based on XML, is a now-obsolete markup language intended for devices that implement the Wireless Application Protocol (WAP) specification, such as mobile phones. It provides navigational support, data input, hyperlinks, text and image presentation, and forms, much like HTML (Hypertext Markup Language). It preceded the use of other markup languages now used with WAP, such as HTML itself, and XHTML (which are gaining in popularity as processing power in mobile devices increases). WML documents are XML documents that validate against the WML DTD (Document Type Definition)[4] . The W3C Markup Validation service (http://validator.w3.org/) can be used to validate WML documents (they are validated against their declared document type).

For example, the following WML page could be saved as "example.wml":

<?xml version="1.0"?>

<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"

"http://www.wapforum.org/DTD/wml_1.1.xml" >

<wml>

<head>

</head>

<p mode="wrap">This is a sample WML page.</p>

</card>

</wml>

A WML document is known as a “deck”. Data in the deck is structured into one or more “cards” (pages) – each of which represents a single interaction with the user.WML decks are stored on an ordinary web server configured to serve the text/vnd.wap.wml MIME type in addition to plain HTML and variants. The WML cards when requested by a device are accessed by a bridge (WAP gateway), which sits between mobile devices and the World Wide Web, passing pages from one to the other much like a proxy. The gateways send the WML pages on in a form suitable for mobile device reception (WAP Binary XML).

Practice Questions and Answers for Unit - I