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Introduction To

Visual Basic 6

Programming language

 Programming is writing instructions for a computer.  Level of programming languages  (^) Machine language – 0s and 1s  (^) Intermediate languatge – assambly language.  (^) High level language – BASIC, C++…

History of BASIC

 Basic --- B eginners' A ll-purpose S ymbolic I nstruction C ode (May,

 MS-BASIC 2.0 (July, 1975)  Visual Basic 1.0 (May,1991)  Visual Basic 6.0 (July 1998)

Why do we learn Visual Basic

 It shares the same principles with other programming languages.  It is good when developing small and handy utility programs.  It is supported by Microsoft.  It is powerful when integrated with Excel and Word.

Step 1 and 2: Problem Identification

and Design

 Identify what needs to be solved  (^) Make diagrams, and equations, etc  Design: Analyze the problem and develop an ALGORITHM and FLOWCHART

Step 3: Source Code

 Creating “Source Code”  (^) Source Code is the instructions for the computer written in Visual Basic programming language  (^) In VB, source code is linked to an object on the form  (^) Designing user interface is also part of the coding.

Step 4b: Interpreting

 Interpreting reads and runs one line of code each time.  You can find “Grammar errors” in this stage.  Advantage:  Good for debugging  (^) Interpreter is easy to program.  Disadvantage:  (^) Slow

Interpreting and Compiling in VB

Step 6: Testing and Running

 Try to run the program by pressing the start button  If it starts running, enter the answers and/or click the buttons to test it  Test your program with boundary and special cases.

Visual Basic Programming

 VB is a programming language that allows you to program in a Windows environment  You create a “Form” with several “Objects”  You set the properties of objects.  You write event handler to response to user’s input.

Definitions

 Form contains the Main Program  Controls are user interface elements (text boxes, commands) in the Form  Forms and Controls are referred to as OBJECTS  Objects have PROPERTIES (features you can change)

Forms in Visual Basic

 You create a form that is your graphical user interface  Has places to input values  Has buttons to click  Has other user interface elements, e.g. Menu, scroll bar…

Object: Dog

 Properties  (^) Height, weight, color, emotion (friendly, hostile) …  (^) Methods  (^) Barking, biting, wagging, singing…  (^) Event handlers  (^) Owner coming in: call wagging, call singing, emotion=friendly;  (^) Intruder coming in: call barking, call biting, emotion=hostile.

Important Controls

 Text Boxes – area where you enter text  Command Buttons – you click on them to do something  Picture Boxes – Output your results.