Explain Three

1. Explain three (3) differentiate between Qbasic and visual basic.

Q BASIC •

VISUAL BASIC

QBASIC runs mainly on DOS, though •

Later versions of Visual Basic did not

there was a short-lived version for Mac OS.

include DOS versions as Microsoft wanted developers to concentrate on Windows applications.

•

•

It is loosely based on GW-BASIC and like

•

It have matured to a RAD (Rapid

gwbasic we had to have an interpeter to run

Application Development) language. VB is

the program, they were not standalone like

eventdriven. That means that we dont have

visual basic programs. Since we can

to create loops to wait on input from users.

declare local variables and use subroutines

When a user for example presses a mouse

it was more stable than gwbasic.

button, a specific piece of code is executed.

Usually as part of an introduction to •

Overall we would class Visual Basic as a

programming, though is fast becoming

Graphics User Interface (GUI). Because as

replaced by more popular compilers. It also

we draw, we write for the program.

has an unofficial community of hobby programmers represented by websites such as qbasicnews. •

•

QBasic, which is a different system is an •

Visual Basic (VB) is a third-generation

Integrated Development Environment (or

event-driven programming language and

IDE)

BASIC

associated development environment (IDE)

programming language that was developed

from Microsoft for its COM programming

by Microsoft.

model.

Qbasic is much easier than visual basic but •

Visual Basic is far more complex than

it is limited as it lacks a few functions than

qbasic and gwbasic, but in the same time

GW-Basic.

it's much easier to use when developing

and

Compiler

for

the

complex desktop application programs.

1. What are the advantages of using Visual Basic ? Explain about it.

•

The structure of the Basic programming language is very simple, particularly as to the executable code.

•

VB is not only a language but primarily an integrated, interactive development environment (IDE).

•

The VB-IDE has been highly optimized to support rapid application development (RAD). It is particularly easy to develop graphical user interfaces and to connect them to handler functions provided by the application.

•

The graphical user interface of the VB-IDE provides intuitively appealing views for the management of the program structure in the large and the various types of entities (classes, modules, procedures, forms).

•

VB provides a comprehensive interactive and context-sensitive online help system.

•

When editing program texts the "IntelliSense" technology informs you in a little popup window about the types of constructs that may be entered at the current cursor location.

•

VB is a component integration language which is attuned to Microsoft's Component Object Model (COM).

•

COM components can be written in different languages and then inegrated using VB.

•

Interfaces of COM components can be easily called remotely via Distributed COM (DCOM), which makes it easy to construct distributed applications.

•

COM components can be embedded in / linked to your application's user interface and also in / to stored documents (Object Linking and Embedding OLE, "Compound Documents").

•

There is a wealth of readily available COM components for many different purposes.

1. Explain the differences between structured and event-driven programming.

STRUCTURED PROGRAMMING •

•

In stuctured programming, you might •

Event-driven is a type of programming

check where the mouse is, and if it's over

which relies on user actions or events.

the textbox and the user clicks, set focus to •

When your mouse rolls over an icon and

the textbox, and start blinking the cursor.

something else happens - it happens as a

If we are in that state, then if the user

result of the mouse-over event firing in

presses keys we add that text to the

your code. •

textbox. •

•

When your mouse rolls over an icon and

Same with the button, check if the mouse is

something else happens - it happens as a

over it, and if they click perform some

result of the mouse-over event firing in

action.

your code.

Structured programming (e.g. C) can just •

Event

as

precursor to Object Oriented Programming.

effectively

have

event

driven

programming. •

EVENT-DRIVEN PROGRAMMING

•

driven

programming

was

the

Anything is an event. From a keystroke, to

Structured Programming is just that - one

a mouse-right-click, anything. Code can be

stack set of code.

written so that when these events happen, your program takes a different course of action.

1. Describe the various files that make up a Visual Basic project : a) Project files •

The .vbp file, called the project file, is a small text file that holds the names of the other files in the project, as well as some information about the VB environment.

a) Form files

•

A form file holds a description of all objects and their properties for the form as well as the Basic Code you have written to respond to the event. Each form in your project is saved in a file with a .frm extension.

a) Multiform project/standart code modules files •

A standart code module is a Basic file with the extension .bas, which is added to the project. These files hold Basic statements that can be accessed from any form. Standart code modules do not contain a form, only code.

a) Class module files •

The Module files are a simple listing of the code with only a simple property, the Name.

•

Class modules can contain more than one type of procedure: sub, function, or property. You can choose the procedure type and its scope when you insert a procedure. Inserting a procedure is like creating a code template into which you enter code.

a) User created control files •

The user controls are the ActiveX controls created by the developers. Their file format is very similar to the form file.

•

User Controls are the controls which are created by the user and they are based on the class System Windows Forms UserControl. Like standard controls, user controls support properties, methods and events. Once a user control is created it can be added to any form or any number of forms like all other controls.

a) ActiveX document form files •

A large selection of ActiveX controls are available to solve many problems. You can purchase controls to display various type of gauges and indicators, display data in grids, send and receive faxes, display video, scan bar codes, display calendars and appointments and perform many other functions.

•

The file for ActiveX controls have extension of .ocx or .vbx.