Submitted by:

Nicole Danielle Mallari

Keith Alison Arellano

Importance of computers

What is a computer?

Computer Programs

Programming Languages

Arithmetic Operations

Comparison (logical) operations

Storage & retrieval operations

Speed & Accuracy

Hardware

System Unit

CPU – control unit & arithmetic logic unit

Main Memory

Peripheral Devices

Input

Output

Secondary Storage

Floppy disk, hard drive, CD, DVD, Flash Drive

Secondary Storage Devices

Used to copy data to & from secondary storage

Storage space measured in Bytes

Kilobyte, Megabyte, Gigabyte, Terabyte

Supercomputers

Mainframes

Minicomputers

Microcomputers

Operating System

User Interface

Command-Line Interface

Graphical User Interface

DOS – Disk Operating System

Command-line

Used to run QBasic

Designed from the BASIC language

Enhanced, menu-driven

Online Help

Structured language

Installed on your H: drive

Double click on QB.exe

Use mouse and arrow keys to navigate

Menu Bar File - Edit View - Search Run - Debug Options - Help

Title Bar

Reference Bar

Immediate Window

Demonstration

File New

Open

Save

Save As

Print

Exit

View SUBs

Split

Output Screen

Run Start

Restart

Continue

Use CLS to clear screen at beginning

Type commands one line at a time

Hit Enter to go to next line

Scroll up & down as needed

CLS

INPUT

PRINT Put text in “double quotes” Use semi-colon ; between quoted text & variable names

Use $ for text variables User$, Instructor$, Title$

Computer Ethics

Hardware Backup data Store media properly

Software Commercial Software Shareware Public-domain Software

There are also special functions called “commands” (also called “instructions”). A “command” tells that the Qbasic interpreter to do something.

The PRINT command tells the Qbasic interpreter to print something to the screen. In this case, the interpreter printed “Hello World ! “.

TIP: Instead of typing PRINT, you can enter a question mark. For

example:

?”Hello World!”

With the PRINT command, you can also print numbersto the screen. Delete the current program (unless you already have) and write the following:

PRINT 512 (or ?512)

<press Enter>

Press F5 to run the program, the program outputs:

512

An expression is something the interpreter calculates (or evaluates). Such us:

1 + 1 (returns 2)

100 – 47 (returns 53)

3 * 34 (returns 102)

80 / 4 (returns 20)

(100 * 3) + (returns 356)

CLS

- An abbreviation that stands for the words Clear Screen . In the above program, when you used CLS on line 60, all the words that were printed to the screen were wiped away.

PRINT

- Writes the screen. There are commands to other things like printer, but that’s to be discussed later. Each new Print command will start printing on a new line. To insert a blank line, don’t specify a string to print. The syntax for “PRINT” is PRINT “[whatever you want to be here]”

END

- It stops the program at that line; that is, anything that’s added after that won’t show. That’s why the PRINT command on line 90 didn’t print anything. The END command can be included in control structures to end the program if a condition is met. This will be discussed with control structures.

Given the state of computer speed today you should not see the paragraph displayed by lines 20 through 50, it should be cleared by the CLS statement on Line 60 before you have a chance to see it.

An operator is a code element that performs an operation on one or more code elements that hold values. Value elements include variables, constants, literals, properties, returns from function and operatorprocedures and expressions.

An expression is a series of value elements combined with operators which yields a new value. The operators act on the value elements by performing calculations, comparisons or other operations.

Visual Basic provides the following types of operators:

Arithmetic Operators perform familiar calculations on numeric values, including shifting their bit patterns.

Comparison Operators Compare two expressions and return a boolean value representing the result of the comparison.

Concatenation operators join multiple strings into single string.

Logical and Bitwise Operators in Visual Basic combine Boolean or numeric values and return a result of the same data type as the values.