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LBSC 690
Session 5AProgramming
LanguagesHow do we learn a language?
Learn by listeningThen reading Then writing
How do we teach programming?Learn to write firstContributes to programming problems
Programming LanguagesPrograms are written in a programming language.Two types:
Procedural and non-procedural (declarative).
Are artificial languages.
Artificial LanguagesConsist of:A set of symbols (an alphabet)A vocabulary
Controlled segment (an authority list)A user-defined segment
SyntaxSemantics
Levels of Languages“Low” to “high”Machine language
Lowest levelAll languages must be translated into this to run on the computerUnique to each platform
Next level:Assembler
Levels (Cont’d)Higher Level Languages:
Basic, Pascal, C, Fortran, Cobol, Visual Basic, Visual C, etc.
Fourth Generation Languages:NOMAD, QBE, etc.
Object Oriented Languages:Smalltalk, C++, Java.
Software ToolsFacilitate writing programs:Compilers & Interpreters.Software Development Environments.
Anatomy of a Web Presentation
The Web PresentationA collection of one or more Web pages
The Web SiteA system on the Internet containing one or more Web presentations
A Web pageSingle element of a Web presentation; contained in a single disk file
Home pageEntry point for a Web presentation
What is HTML?HyperText Markup Language.
Based on Standard Generalized Markup Language (STML).Developed by Tim Berners-Lee
Describes the structure of a document.
Not its presentation.Does not describe page layout.
Designed to be used cross-platform.
HTML is a Markup Language
Start with text and add special tags around words and paragraphs.Tags indicate different parts of a page and produce different effects in the browser.HTML has a given, defined set of tags.
Users cannot create their own.
HTML VersionsHTML 2.0.
Base set of tags.
HTML 3.2.Second release.
HTML 4.0.Current generation.Includes new features for flexibility.
HTML 4.01.Has corrections for 4.0.
What do HTML Files look like?
Contain:Text of page itself,HTML tags indicating page elements, structure, formatting and hypertext links to other pages or to included media.
Look at HTML sources.For example, with Netscape use:
Creating PageUse a text editor.
Saves files in ASCII format.In Unix, pico is a text editor,In Windows, Notepad and DOS Edit are text editors.
View your created page with a browser.
TagsAll text and HTML commands require beginning and ending HTML tags:<HTML>… your page…</HTML> {The forward slash indicates
the end.}.This tag indicates that the content of this file is in HTML.
Tags (Cont’d.)<HEAD> tag:
Specifies that the lines in it are prologue, e.g., the title:
<TITLE>.
<BODY> tag:Encloses the remainder of the text
and other contents (links, pictures, etc).
<H1> tags are Headings that divide sections of text.(Can be up to 6 levels).
Tags (Cont’d).<P> tags indicate paragraphs.HTML defines five kinds of lists:
Numbered lists: <LI>.Bulleted or ,unordered, lists: <UL>.Glossary lists: <DL>.Menu lists: <MENU>.
Comments: <!-- This is a comment.-->.
Sources of Help for HTMLSpecifications: www.w3.org/TR/hrml401/cover.html.A Beginner’s Guide to HTML:www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html.Laura Lemay,Teach yourself Web Publishing with HTML 4 in a Week, Fourth Edition,SamsNet.1997.Ed Tittel, HTML for Dummies, IDG Books, 1997.
