Objectives

• Machine language vs.. High-level language• Procedure-oriented, object-oriented, and event-

driven languages• Background of Visual Basic• VB Integrated Development Environment• Online documentation and Help features

Software

• Application Software – Word Processors– Database s/w– Spreadsheets– Painting programs– Web browsers, email

programs

• System Software– Operating Systems

• Windows• Macintosh OS• Unix• Linux

– Drivers

Software is comprised of instructions that get a computer to perform a task.

Software

Computer

Hardware

Processing Unit

Output Unit

Input Unit

Memory Unit

System Software

Application Software

Operating System

Language Processor

Utility Software

General Software

CustomizedSoftware

Copyright 1999 Prentice-Hall, Inc. 4Exploring MS Visual Basic 6

Application Programs

Program - detailed set of instructions for a computer to execute

Application programs (applications or apps) - self-contained collection of programs that perform a task for the end user

Programming language - formal language used to give instructions to computers

Programming Languages

• Programming languages allow programmers to code software.

• The three major families of languages are:– Machine languages– Assembly languages– High-Level languages

Software

Collection of Programs

Set of Commands

( Pre Defined )

Programming Language

Programmer

Copyright 1999 Prentice-Hall, Inc. 7Exploring MS Visual Basic 6

History of Programming Languages

• Machine language• Procedure-oriented languages• Object-oriented languages• Event-driven languages• Natural languages

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History of Programming Languages

• Machine Language – different for each computer processor

• Procedure-Oriented Languages– FORTRAN– COBOL– Pascal– C– Ada

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History of Programming Languages

• Object-oriented languages– Smalltalk– C++– Ada 95

• Event-driven languages– Visual Basic– most Visual languages

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History of Programming Languages

• Natural languages– computer will accept a user’s native or natural

language, such as English– Researchers continue to work in this area

VISUAL BASIC

Why VB? Rationale…

• Easy for beginners to produce a working program

• Capable of high end programs• Graphical• OOP (for the most part)• Affordable• Many free resources available

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Copyright 1999 Prentice-Hall, Inc. 13Exploring MS Visual Basic 6

Background of Visual Basic

• BASIC– Beginner’s All-purpose Symbolic Instruction Code– By John Kemeny and Thomas Kurtz – Designed to teach programming to beginners– BASIC language interpreter, one of Microsoft’s first

products

Copyright 1999 Prentice-Hall, Inc. 14Exploring MS Visual Basic 6

Background of Visual Basic

• BASIC – Beginners' All purpose Symbolic Instruction Code– Included with DOS– QBASIC - included with DOS Version 5 - subset of BASIC

• Visual Basic– 1992 - Visual Basic 1 for Windows 3– Visual Basic 4 - for Windows 95– Visual Basic 5 - for Office 97– Visual Basic 6 - for Windows 98 & Office 2000

VISUAL BASIC

• GUI– (Graphical user interface )

• IDE – (Integrated development environment)

• EDP– (Event Driven Programming)

• The GUI environment is event-driven• An event is an action that takes place within a

program– Clicking a button (a Click event)– Keying in a TextBox (a TextChanged event)

• Visual Basic controls are capable of detecting many, many events

• A program can respond to an event if the programmer writes an event procedure

Slide 1- 16

Event Driven Programming: Events

Starting VB 6.0

• Go to Start • All Programs• Microsoft Visual Studio 6.0• Microsoft Visual Basic 6.0

Select

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Toolbox

Form Designer Window

Code Editor Window

Project Explorer

Properties window

Form Layout Window

Visual Basic 6 Interactive Development Environment

Elements of the Integrated Development Environment

• Application icon• Application name• Context menus• Controls• Current project• Design view mode• Title bar

• Major windows– Form Designer– Form Layout– Toolbox– Project Explorer– Object Browser– Properties– Code Editor– Immediate, Locals, Watch