HTML & History of HTML

Hypertext Markup Language (HTML) 

Hypertext Markup Language (HTML) is the standard markup language for creating web pages and web applications. With Cascading Style Sheets (CSS) and JavaScript, it forms a triad of cornerstone technologies for the World Wide Web.^[4]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. The World Wide Web Consortium (W3C), maintainer of both the HTML and the CSS standards, has encouraged the use of CSS over explicit presentational HTML since 1997.^[5]  

Tim Berners-Lee

History

Development

In 1980, physicist Tim Berners-Lee, a contractor at CERN, proposed and prototyped ENQUIRE, a system for CERN researchers to use and share documents. In 1989, Berners-Lee wrote a memo proposing an Internet-based hypertext system.^[6] Berners-Lee specified HTML and wrote the browser and server software in late 1990. That year, Berners-Lee and CERN data systems engineer Robert Cailliau collaborated on a joint request for funding, but the project was not formally adopted by CERN. In his personal notes^[7] from 1990 he listed^[8]"some of the many areas in which hypertext is used" and put an encyclopedia first.
The first publicly available description of HTML was a document Tim Berners-Leecalled "HTML Tags", first mentioned on the Internet by Tim Berners-Lee in late 1991.^[9][10] It describes 18 elements comprising the initial, relatively simple design of HTML. Except for the hyperlink tag, these were strongly influenced by SGMLguid, an in-house Standard Generalized Markup Language(SGML)-based documentation format at CERN. Eleven of these elements still exist in HTML 4.^[11]
HTML is a markup language that web browsers use to interpret and compose text, images, and other material into visual or audible web pages. Default characteristics for every item of HTML markup are defined in the browser, and these characteristics can be altered or enhanced by the web page designer's additional use of CSS. Many of the text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML, which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS (Compatible Time-Sharing System) operating system: these formatting commands were derived from the commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements (nested annotated ranges with attributes) rather than merely print effects, with also the separation of structure and markup; HTML has been progressively moved in this direction with CSS.
Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by the Internet Engineering Task Force (IETF) with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language (HTML)" Internet Draft by Berners-Lee and Dan Connolly, which included an SGML Document type definition to define the grammar.^[12][13] The draft expired after six months, but was notable for its acknowledgment of the NCSA Mosaic browser's custom tag for embedding in-line images, reflecting the IETF's philosophy of basing standards on successful prototypes.^[14]Similarly, Dave Raggett's competing Internet-Draft, "HTML+ (Hypertext Markup Format)", from late 1993, suggested standardizing already-implemented features like tables and fill-out forms.^[15]                                                                   After the HTML and HTML+ drafts expired in early 1994, the IETF created an HTML Working Group, which in 1995 completed "HTML 2.0", the first HTML specification intended to be treated as a standard against which future implementations should be based.^[16]Further development under the auspices of the IETF was stalled by competing interests. Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium (W3C).^[17] However, in 2000, HTML also became an international standard (ISO/IEC 15445:2000). HTML 4.01 was published in late 1999, with further errata published through 2001. In 2004, development began on HTML5 in the Web Hypertext Application Technology Working Group (WHATWG), which became a joint deliverable with the W3C in 2008, and completed and standardized on 28 October 2014.^[18]

C Basic commands & Explanation

C Basic commands	Explanation
#include <stdio.h>	This is a preprocessor command that includes standard input output header file(stdio.h) from the C library before compiling a C program
int main()	This is the main function from where execution of any C program begins.
{	This indicates the beginning of the main function.
/*_some_comments_*/	whatever is given inside the command “/*   */” in any C program, won’t be considered for compilation and execution.
printf(“Hello_World! “);	printf command prints the output onto the screen.
getch();	This command waits for any character input from keyboard.
return 0;	This command terminates C program (main function) and returns 0.
}	This indicates the end of the main function.

2. A SIMPLE C PROGRAM:

Below C program is a very simple and basic program in C programming language. This C program displays “Hello World!” in the output window. And, all syntax and commands in C programming are case sensitive. Also, each statement should be ended with semicolon (;) which is a statement terminator.

C

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#include <stdio.h> int main() {    /* Our first simple C basic program */    printf("Hello World! ");    getch();    return 0; }

C Programing Overview

Overview

Dennis Ritchie (right), the inventor of the C programming language, with Ken Thompson

Like most imperative languages in the ALGOL tradition, C has facilities for structured programming and allows lexical variable scope and recursion, while a static type system prevents many unintended operations. In C, all executable code is contained within subroutines, which are called "functions" (although not in the strict sense of functional programming). Function parameters are always passed by value. Pass-by-reference is simulated in C by explicitly passing pointer values. C program source text is free-format, using the semicolon as a statement terminator and curly braces for grouping blocks of statements.

The C language also exhibits the following characteristics:

• There is a small, fixed number of keywords, including a full set of control flowprimitives: for, if/else, while, switch, and do/while. User-defined names are not distinguished from keywords by any kind of sigil.
• There are a large number of arithmetical and logical operators, such as +, +=, ++, &, ~, etc.
• More than one assignment may be performed in a single statement.
• Function return values can be ignored when not needed.
• Typing is static, but weakly enforced: all data has a type, but implicit conversions may be performed.
• Declaration syntax mimics usage context. C has no "define" keyword; instead, a statement beginning with the name of a type is taken as a declaration. There is no "function" keyword; instead, a function is indicated by the parentheses of an argument list.
• User-defined (typedef) and compound types are possible.
  • Heterogeneous aggregate data types (struct) allow related data elements to be accessed and assigned as a unit.
  • Union is a structure with overlapping members; only the last member stored is valid.
  • Array indexing is a secondary notation, defined in terms of pointer arithmetic. Unlike structs, arrays are not first-class objects; they cannot be assigned or compared using single built-in operators. There is no "array" keyword, in use or definition; instead, square brackets indicate arrays syntactically, for example month[11].
  • Enumerated types are possible with the enum keyword. They are freely interconvertible with integers.
  • Strings are not a separate data type, but are conventionally implemented as null-terminated arrays of characters.
• Low-level access to computer memory is possible by converting machine addresses to typed pointers.
• Procedures (subroutines not returning values) are a special case of function, with an untyped return type void.
• Functions may not be defined within the lexical scope of other functions.
• Function and data pointers permit ad hoc run-time polymorphism.
• A preprocessor performs macro definition, source code file inclusion, and conditional compilation.
• There is a basic form of modularity: files can be compiled separately and linked together, with control over which functions and data objects are visible to other files via static and extern attributes.



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• Complex functionality such as I/O, string manipulation, and mathematical functions are consistently delegated to library routines.

While C does not include some features found in some other languages, such as object orientation or garbage collection, such features can be implemented or emulated in C, often by way of external libraries (e.g., the Boehm garbage collector or the GLib Object System).

Relations to other languages

Many later languages have borrowed directly or indirectly from C, including C++, C#, Unix's C shell, D, Go, Java, JavaScript, Limbo, LPC, Objective-C, Perl, PHP, Python, Rust, Swift, and Verilog (hardware description language)^[5]. These languages have drawn many of their control structures and other basic features from C. Most of them (with Python being the most dramatic exception) are also very syntactically similar to C in general, and they tend to combine the recognizable expression and statement syntax of C with underlying type systems, data models, and semantics that can be radically different.

    for more information click on onhttps://en.wikipedia.org/wiki/C_%28programming_language%29