BASIC Programming Language

BASIC
Includes Visual BASIC, VB.net, QuickBasic,
PowerBasic, GW Basic, PowerBASIC and the
BASIC Programming Language
Shane Estavillo
Jeffrey James Valerio

BASIC
eginner
’sll
Purposeymboli
c
nstructionod
e
It is a family of high-level programming languages, in other words, a multi
platform language.
One of the earliest and simplest high-level languages with commands
similar to English. It can be learned with relative ease even by
schoolchildren and novice programmers.
It is in widespread use but has gotten little respect.

BASIC
The language was based partly on the
FORTRAN IV and partly on the ALGOL
60, with additions to make it suitable for
timesharing.
FORTRAN
IV (1962)
ALGOL 60
(1960
BASIC
(1964)

Genealogy of BASIC
The language was based partly on the
FORTRAN IV and partly on the ALGOL
60, with additions to make it suitable for
timesharing.
BASI
C
(1964
)
QuickBASIC
(1988)
Visual
BASIC
(1990)

BASIC was first implemented on
the GE-265 mainframe which
supported multiple terminals.

Original BASIC Language
Overview
Very small and oddly, was not
interactive.
No means of getting input data from
terminal.
Programs were typed in, compiled and
run, in sort of batch-oriented way.
Had only 14 different statement types
and a single data type, floating point,
referred to as “numbers”.
Overall, it was very limited language
though quite easy to learn.

Significant Language
Features
Loops
Input from the keyboard
Menu Driven Applications
System Commands - These are words
that make the system perform a
specific task immediately.

Features
User-Defined Functions
Arrays, sorting, and searches
Areas of Application
BASIC has many strong points, such as:
Easy to learn for beginners
Structured Programming
Subroutines
Built-In Functions

Features
Adds powerful additional features for
the advanced user
Is designed for interactive use rather
than batch work
Lends itself to learning by hands-on
practical use
and is therefore suitable for both the
professional and non-professional.

The goals of the system were:
1. It must be easy for non-science
students to learn and use.
2. It must be pleasant and friendly.
3. It must provide fast turnaround for
homework.
4. It must allow free and private access.
5. It must consider user time more
important than computer time.

The eight design principle of
BASIC:
1. Be easy for beginners to use.
2. Be a general-purpose programming
language.
3. Allow advanced features to be added for
experts (while keeping the language simple
for beginners).
4. Be interactive.
5. Provide clear and friendly error messages.
6. Respond quickly for small programs.
7. Not to require an understanding of
computer hardware.
8. Shield the user from the operating system.

Evaluation and Criticisms
Poor structure of programs written in
it.
Early versions were not meant for
serious programs of any significant
size, though later versions can handle
such tasks.
Edsger W. Djikstra, a highly-respected
computer proffessional that the use of
GoTo statements, particularly in
BASIC, promoted poor programming
practices.

Then why BASIC is
successful?
Ease with which it can be learned and
the ease with which it can be
implemented, even on very small
computers.

The original
BASIC was
designed in 1964
by John George
Kemeny (right)
and Thomas
Eugene Kurtz
(left) at Dartmouth
College (now
Dartmouth
University) in New
Hampshire, USA

Brief History of BASIC
Before the mid-1960s, computers were
extremely expensive and used only for
special-purpose tasks.
As prices decreased, from research
aabs, computing went into commercial
use.
Newer computer systems then supported
time-sharing, a system that allows
multiple users or processes to use
the CPU and memory.

In the following years, as other dialects
of BASIC appeared, Kemeny and Kurtz’s
original BASIC dialect became known as
Dartmouth BASIC.
When it was implemented in
minicomputers DEC PDP Series and the
Data General Nova; HP-Time Shared
BASIC System (1960s), BASIC acted
merely as an interpreter rather than a
compiler.

DEC-PDP
ALTAIR 8800
NOVA
SYSTEM

It was the introduction of Altair 8800
“kit” microcomputer in 1975 that
provided BASIC a path to
universality.
BASIC provided faster memory
access for audio tapes and suitable
text editors that time.

In order to promote the language, it
was available FREE OF CHARGE.
One of the first to appear was the Tiny
Basic originally written by Li-Chen
Wang, a simple BASIC
implementation. For 8080 machines
like the Altair.

MITS then released Altair BASIC,
developed by Bill Gates and Paul
Allen in 1975.
Microsoft BASIC (widely known as
MBASIC or M BASIC)was soon
bundled with an original floppy disk
based CP/M computers.

The Atari 8-bit family had their own
Atari BASIC that was modified in order
to fit on 8 kB ROM cartridge.
The BBC published BBC BASIC,
developed for them by Acorn
Computers Ltd, incorporating many
extra structuring keywords.

As early as 1979 Microsoft was in
negotiations with IBM to supply them
with a version of BASIC. Microsoft
sold several versions of BASIC for
MS-DOS/ PC-DOS including BASICA,
GW-BASIC (a BASICA-compatible
version that did not need IBM's ROM)
and QuickBASIC.

Turbo Pascal & Turbo C++-publisher
Borland published Turbo BASIC 1.0 in
1985 (successor versions are still
being marketed by the original author
under the name PowerBASIC).

These languages introduced many
extensions to the original home
computer BASIC, such as improved
string manipulation and graphics
support, access to the file system and
additional data types. More important
were the facilities for structured
programming, including additional
control structures and proper
subroutines supporting local variables.

The Shift of BASIC into Visual
BASIC
The Visual BASIC introduced by
Microsoft is difficult to consider to be
really the original BASIC, since of its
major shift towards being object-
oriented and event-driven in
perspective.
VB Version 3.0 is widely considered
the first relatively stable version.

Basic BASIC Syntax
SYNTAX
TYPICAL BASIC KEYWORDS
Data manipulation
LET: assigns a value (which may be
the result of an expression) to a
variable.
DATA: holds a list of values which are
assigned sequentially using the READ
command.

Program flow control
IF ... THEN ... ELSE: used to perform comparisons or
make decisions.
FOR ... TO ... {STEP} ... NEXT: repeat a section of code
a given number of times. A variable that acts as a
counter is available within the loop.
WHILE ... WEND and REPEAT ... UNTIL: repeat a
section of code while the specified condition is true. The
condition may be evaluated before each iteration of the
loop, or after.
DO ... LOOP {WHILE} or {UNTIL}: repeat a section of
code Forever or While/Until the specified condition is
true . The condition may be evaluated before each
iteration of the loop, or after.
GOTO: jumps to a numbered or labelled line in the
program.

Program flow control
GOSUB: jumps to a numbered or labelled line, executes
the code it finds there, but upon encountering the
RETURN Command, it jumps back to the line following
the line from which the jump occurred. This is used to
implement subroutines.
ON ... GOTO/GOSUB: chooses where to jump based
on the specified conditions. See Switch statement for
other forms.
DEF FN: a pair of keywords introduced in the early
1960s to define functions. The original BASIC functions
were modelled on FORTRAN single-line functions.
BASIC functions were one expression with variable
arguments, rather than subroutines, with a syntax on
the model of DEF FND(x) = x*x at the beginning of a
program. Function names were restricted to FN+one
letter.

I/O: Input and Output
PRINT: displays a message on the
screen or other output device.
INPUT: asks the user to enter the
value of a variable. The statement
may include a prompt message.
TAB or AT: sets the position where the
next character will be shown on the
screen or printed on paper.

Miscellaneous Syntax
REM: holds a programmer's comment or REMark; often
used to give a title to the program and to help identify
the purpose of a given section of code.
USR: transfers program control to a machine language
subroutine, usually entered as an alphanumeric string
or in a list of DATA statements.
TRON: turns on a visual, screen representation of the
flow of BASIC commands by displaying the number of
each command line as it is run. The TRON command,
largely obsolete now, stood for, TRace ON. This meant
that command line numbers were displayed as the
program ran, so that the command lines could be
traced. This command allowed easier debugging or
correcting of command lines that caused problems in a
program.

Miscellaneous Syntax
Problems included a program terminating without
providing a desired result, a program providing
an obviously erroneous result, a program running
in a non-terminating loop, or a program otherwise
having a non-obvious error. (The command
TRON has also entered popular cultural with the
name of the 1982 Disney movie, "TRON," with a
subsequent movie, "TRON: Legacy," a television
series, "TRON: Uprising," and two video games,
"TRON: Legacy," and "TRON:Evolution." In each
of these entertainments the TRON command is
personified as a character that battles against
evil elements in programs.)
TROFF: turns off the display of the number of
each command line as command lines run after
the command TRON has been used.

DATA TYPES AND VARIABLES
Minimal versions of BASIC had only integer variables and one-letter
variable names. More powerful versions had floating-point
arithmetic, and variables could be labelled with names six or more
characters long.
String variables are usually distinguished in many microcomputer
dialects by having $ suffixed to their name, and string values are
typically enclosed in quotation marks.
Arrays in BASIC could contain integers, floating point or string
variables.
Some dialects of BASIC supported matrices and matrix operations,
useful for the solution of sets of simultaneous linear algebraic
equations. These dialects would support matrix operations such as
assignment, addition, multiplication (of compatible matrix types), and
evaluation of a determinant. Microcomputer dialects often lacked this
data type and required a programmer to provide subroutines to carry
out equvalent operations.
BASIC (PROGRAMMING LANGUAGE) IS AN EARLIER VERSION
OF VISUAL BASIC. VB IS MODIFIED FOR PC USER U CAN SAY
IT IS A GUI VERSION OF BASIC.

The next set of
discussions are
directly based on
the Original
Manual of the
BASIC
Programming
Language
designed for use
in the Darthmouth
Time-Sharing
BASIC Programming

Expressions, Numbers and
Variables

Types of BASIC
Unstructured BASIC
Structured BASIC
Object-Oriented BASIC or Visual
BASIC

Unstructured BASIC
These are the first-generation BASIC
languages such as MSX BASIC and
GW BASIC.
Most support:
Simple Data Types
Loop Cycles
Arrays

10 PRINT "Hello World! "
20 GOTO 10
Sample Program for GW
BASIC

Hello World !Hello World! Hello World!
Hello World! Hello World! Hello World!

10 PRINT "Hello World! "
20 GOTO 10
This program prints the phrase “Hello
World! “ infinitely.
BASIC

10 INPUT "ENTER TWO NUMBERS
SEPARATED BY A COMMA:
20 LET S = N1 + N2
30 LET D = N1 - N2
40 LET P = N1 * N2
50 LET Q = N1 / N2
60 PRINT "THE SUM IS ", S
70 PRINT "THE DIFFERENCE IS ", D
80 PRINT "THE PRODUCT IS ", P
90 PRINT "THE QUOTIENT IS ", Q
100 END
BASIC

ENTER TWO NUMBERS SEPARATED BY A COMMA:
THE SUM IS 6
THE DIFFERENCE IS 2
THE PRODUCT IS 8
THE QUOTIENT IS 2

Structured BASIC
Second Generation BASICs are
structured and procedure-oriented
programming.
Line numbering is omitted and then
replaced with labels for GoTo and
procedure.
QuickBASIC and PowerBASIC are
examples.

Sample PowerBASIC
Program
Function PBMain
Print "Hello, World!"
Waitkey$
End Function

Sample QuickBASIC Program
#COMPILE EXE
Function PBMain() as Long
MsgBox "Hello World"
End Function

BASIC with Object-Oriented
features
Third generation BASIC dialects such
as Visual Basic and StarOffice Basic
introduced features to support object-
oriented and event-driven
programming paradigm.
Most built-in procedures and functions
now represented as methods of
standard objects rather than operators
.

Visual BASIC
Visual basic is derived form the BASIC
programming languages, it is a Microsoft
window programming language, visual
basic program are created in an
integrated development environment
(IDE), which allows the programmer to
create run and design visual basic
programs conveniently it’s also allow a
programmer to create working programs
in a fraction of time that normally takes to
code programs without using IDES.

Visual BASIC
The wide spread use of BASIC
Language with various types of
computer (sometimes called hardware
platform) led to many enhancement to
the languages with the development of
Microsoft windows graphical user
interface (GUI) in the late 1980’s and
the early 1990’s, the natural evolution
of basic was visual basic which was
created by Microsoft corporation in
1991.

Procedural BASIC: True
BASIC
True BASIC, C, Fortran, and Pascal are
examples of procedural languages. Procedural
languages change the state or memory of the
machine by a sequence of statements. True
BASIC is similar to F (a subset of Fortran 90) and
has excellent graphics capabilities which are
hardware independent. True BASIC programs
can run without change on computers running
the Macintosh, Unix, and Windows operating
systems. We will consider version 3.0 (2.7 on the
Macintosh) of True BASIC. Version 5 includes
the ability to build objects such as buttons, scroll
bars, menus, and dialog boxes. However,
because we wish to emphasize the similarity
between True BASIC and other procedural
languages such as C, F, and Java, we do not
consider these features.

BASIC
PROGRAM product
! taken from Chapter 2 of Gould &
Tobochnik
LET m = 2 ! mass in
kilograms
LET a = 4 ! acceleration in
mks units
LET force = m*a ! force in
Newtons
PRINT force
END

BASIC
The features of True BASIC included
in the above program include:
The first statement is an optional
PROGRAM header. The inclusion of a
program header is good programming
style.

BASIC
Comment statements begin with ! and
can be included anywhere in the
program.
PROGRAM, LET, PRINT, and END
are keywords (words that are part of
the language and cannot be
redefined) and are given in upper
case. The case is insignificant (unlike
C, F, and Java). The DO FORMAT
command converts keywords to upper
case.

BASIC
The LET statement causes the
expression to the right of the = sign to be
evaluated and then causes the result to
be assigned to the left of the = sign. (The
LET statement reminds us that the
meaning of the = symbol is not the same
as equals.) It is not necessary to type
LET, because the DO FORMAT
command automatically inserts LET
where appropriate. The LET statement
can be omitted if the OPTION NOLET
statement is included.

BASIC
True BASIC does not distinguish
between integer numerical variables and
floating point numerical variables and
recognizes only two types of data:
numbers and strings (characters). The
first character of a variable must be a
letter and the last must not be an
underscore.
The PRINT statement displays output on
the screen.
The last statement of the program must
be END.

Sample True BASIC with
input
PROGRAM product2
INPUT m
INPUT prompt "acceleration a (mks
units) = ": a
LET force = m*a ! force
in Newton's
PRINT "force (in Newtons) ="; force
END

Visual BASIC
Visual basic is the worlds most widely use
RAD language, (Rapid Application
Development (RAD) is the process of rapidly
creating an application. Visual Basic provide
a powerful features such as graphical user
interface, events handling assess to Win 32
API, object-oriented features, error handling,
structured programming and much more. Not
until Visual Basic appeared, developing
Microsoft windows based application was a
difficult and cumbersome process. Visual
basic greatly simplifies window application
development. The advantages of visual basic
programming language

Visual BASIC
VB 1.0 was introduced in 1991. The drag
and drop design for creating the user
interface is derived from a prototype form
generator developed by Alan Cooper and
his company called Tripod. Microsoft
contracted with Cooper and his
associates to develop Tripod into a
programmable form system for Windows
3.0, under the code name Ruby (no
relation to the Ruby programming
language).

Visual BASIC Features
Visual Basic gives a disciplined
approach to writing programs that are
clearer than unstructured programs,
easier to test, debug and can be easily
modify.
It allows for the creation of powerful
and professional looking application
with less time and coding. It allows for
strong typing i.e. has wide variety of
input data types and support Rapid
Application Development (RAD).

Visual BASIC Features
It has a complete edifying and debugging
facilities and has the ability to generate a
Dynamic Link Libraries (DLL`S), it
allows for easier management of
document and it is easy to learn.
Visual Basic is a complete form of
package for building user interface
Visual basic is a fairly easy language to
pick up. However, it is generally not used
to make very large applications. VB was
also created for MS Windows.

Sample VB Program
Private Sub Form_Load()
' Execute a simple message box
that says "Hello, World!"
MsgBox "Hello, World!"
End Sub

REMEMBER
Please do not be mistaken by BASIC
and Visual BASIC.
BASIC (PROGRAMMING
LANGUAGE) IS AN EARLIER
VERSION OF VISUAL BASIC.
Visual BASIC is MODIFIED for
personal computer users, so we can
say that it is a GUI VERSION of
BASIC.

Prepared by:
Jeffrey James L. Valerio
Shane Estavillo

BASIC Programming Language

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