generations of programming languages first generation machine language second generation assembly...

Generations of Programming Languages

First generation Machine Language

Second Generation Assembly Language

Third Generation Procedural language such as Pascal, C, Basic etc.

Fourth Generation Non-procedural language, more natural.

1

Machine language

10110000 01100001

2

Assembly Language

mov al, 061h

3

Popular Programming Languages

FORTRAN—the oldest high-level programming language; designed for scientific and mathematical applications.

4

Popular Programming Languages, Cont’d.

COBOL—designed for business transaction processing.

5

Popular Programming Languages, Cont’d.

Pascal—designed to teach structured programming; useful for math and science applications.

6

Popular Programming Languages, Cont’d.

BASIC—an easy-to-learn beginner’s programming language.

Visual Basic—an object-oriented, third-generation version of BASIC.

7

Popular Programming Languages, Cont’d.

C, C++, C#—versions of the highly efficient C programming language; C++ and C# are object-oriented.

8

Popular Programming Languages, Cont’d.

Java—object-oriented programming language commonly used for Web applications. Platform independence—Java programs can run on

any platform that supports the Java Virtual Machine.

9

Popular Programming Languages, Cont’d.

Other high-level languages:

Ada APL LISP Logo

11

PL/1 Prolog RPG SmallTalk

SQL – 4GL12

Select address from PatientsWhere Patients.name = “Johnson”And Patients.age < 65

HIMA 4160

JavaScript

What is JavaScript

Programming language designed for webpage

To increase interactivity and dynamicsApplications

Form validation Shopping cart Calculations Special graphic and text effects Online email systems (Yahoo, Hotmail) Online mapping (Google Map) Online productivity suite (Google doc, ZOHO)

Before talking about JavaScript, we need to talk

about form in HTML

HTML Form

Explanation: http://www.w3schools.com/html/html_forms.asp

JavaScript Syntax

Unlike HTML, JavaScript is case sensitive. Dot Syntax is used to combine terms.

e.g., document.write("Hello World")

Certain characters and terms are reserved. JavaScript is simple text (ASCII).

JavaScript Terminology

JavaScript programming uses specialized terminology.

Understanding JavaScript terms is fundamental to understanding the script. Objects, Properties, Methods, Events, Functions,

Values, Variables, Expressions, Operators.

Objects

Objects refers to windows, documents, images, tables, forms, buttons or links, etc.

Objects should be named. Objects have properties that act as modifiers.

Properties

Properties are object attributes. Object properties are defined by using the

object's name, a period, and the property name. e.g., background color is expressed by: document.bgcolor .

document is the object. bgcolor is the property.

Methods

Methods are actions applied to particular objects. Methods are what objects can do. e.g., document.write(”Hello World") document is the object. write is the method.

Events

Events associate an object with an action. e.g., the onMouseover event handler action can

change an image. e.g., the onSubmit event handler sends a form.

User actions trigger events.

Functions

Functions are named statements that performs tasks. e.g., function doWhatever () {statement here}

The curly braces contain the statements of the function.

JavaScript has built-in functions, and you can write your own.

Values

Values are bits of information. Values types and some examples include:

Number: 1, 2, 3, etc. String: characters enclosed in quotes. Boolean: true or false. Object: image, form Function: validate, doWhatever

Variables

Variables contain values and use the equal sign to specify their value.

Variables are created by declaration using the var command with or without an initial value state. e.g. var month; e.g. var month = “April”;

Expressions

Expressions are commands that assign values to variables.

Expressions always use an assignment operator, such as the equals sign. e.g., var month = “May”; is an

expression.

Expressions end with a semicolon.

Operators

Operators are used to handle variables. Types of operators with examples:

Arithmetic operators, such as plus. Comparisons operators, such as equals. Logical operators, such as and. Control operators, such as if. Assignment and String operators.

JavaScript Syntax: Dynamic Typing

Idea No need to declare variable type A value is only checked from proper type when it is

operated upon

Examplevar x = 5; //int

x = 5.5; //float

x = “five point five” //String

y=x/2 //wrong

Methods of Using JavaScript.

1. JavaScripts can reside in a separate page. 2. JavaScript can be embedded in HTML

documents -- in the <head>, in the <body>, or in both.

3. JavaScript object attributes can be placed in HTML element tags.e.g., <body onLoad="alert('WELCOME')">

1. Using Separate JavaScript Files.

Linking can be advantageous if many pages use the same script.

Use the source element to link to the script file.<script src="myjavascript.js”

language="JavaScript1.2”

type="text/javascript">

</script>

2. Embedding JavaScript in HTML.

When specifying a script only the tags <script> and </script> are essential, but complete specification is recommended:

<script language="javascript”

type="text/javascript">

<!-- Begin hiding

window.location=”index.html"

// End hiding script-->

</script>

Using Comment Tags

HTML comment tags should bracket any script.

The <!-- script here --> tags hide scripts in HTML and prevent scripts from displaying in browsers that do not interpret JavaScript.

Double slashes // are the signal characters for a JavaScript single-line comment.

3. Using JavaScript in HTML Tags.

Event handlers like onMouseover are a perfect example of an easy to add tag script.

<a href=”index.html”

onMouseover="document.logo.src='js2.gif'"

onMouseout="document.logo.src='js.gif'">

<img src="js.gif" name="logo">

</a>

Creating an Alert Message

The following script in the <body> tag uses the onLoad event to display an Alert window

The message is specified within parenthesis.

<body onLoad="alert('WELCOME. Enjoy your visit. Your feedback can improve cyberspace. Please let me know if you detect any problems. Thank you.')">

Generating HTML Dynamically

Idea Script is interpreted as page is loaded, and uses document.write or document.writeln to insert HTML at the location the script occurs

Template…<body>Regular HTML

<script type=“text/javascript”><!-- Build HTML Here// --> </script>

More regular HTML</body>

A Simple Script

<html><head>

<title>First JavaScript Page</title><head>

<body><h1>First Javascript Page</h1>

<script type=“text/javascript”><!-- document.write(“<hr>”);document.write(“Hello World Wide Web”);document.write(“<hr>”);//--></script>

</body><html>

Simple Script, Result

Monitoring User Events

Use various onXxx attributes related to HTML tags onClick onLoad onMouseOver onFocus …

User Events, Example

<html><head>

<title>Simple JavaScript Button</title><script type=“text/javascript”><!-- function dontClick(){

alert(“I told you not to click!”);}//--></script>

</head>

<body bgcolor=“white”><h1>Simple JavaScript Button</h1><form>

<input type=“button” value = “Don’t click Me” onClick=“dontClick()”></form></body></html>

User Events, Result

JavaScript Syntax: Function Declaration

Declaration syntax Functions are declared using the function reserved word The return value is not declared, nor are the types of the

arguments

Example:function square(x){return(x*x);

}

function factorial(n){if (n <= 0){

return(1);} else{

return (n * factorial(n-1));}

}

Next Class

Bring your laptop on Thursday.