COMPUTER PROGRAMMING

CHAPTER 9
(Computer Programming)

PROGRAMMING
• Programming or coding is
the process of designing,
writing, testing, debugging
/ troubleshooting, and
maintaining the source code
of computer programs.
• This source code is written
in a programming language.
The code may be a
modification of an existing
source or something
completely new.

PURPOSE OF PROGRAMMING
• The purpose of programming is to create a
program that exhibits a certain desired
behaviour (customization).
• The process of writing source code often
requires expertise in many different subjects,
including knowledge of the application
domain, specialized algorithms and
formal logic.

QUALITY REQUIREMENTS
• Whatever the approach to software
development may be, the final
program must satisfy some
fundamental properties.
• The following properties are among
the most relevant:

EFFICIENCY / PERFORMANCE
• Is the amount of system resources a
program consumes (processor time,
memory space, slow devices such as
disks, network bandwidth and to some
extent even user interaction): the less, the
better.
• This also includes correct disposal of
some resources, such as cleaning up
temporary files and lack of memory leaks
.

RELIABILITY
• Is how often the results of a program are
correct.
• This depends on conceptual correctness of
algorithms, and minimization of
programming mistakes, such as mistakes in
resource management (e.g., buffer overflows
and race conditions) and logic errors (such
as division by zero or off-by-one errors).

ROBUSTNESS
• Is how well a program anticipates
problems not due to programmer error.
• This includes situations such as incorrect,
inappropriate or corrupt data,
unavailability of needed resources such as
memory, operating system services and
network connections, and user error.

USABILITY
• Is the ergonomics of a program: the ease
with which a person can use the program for
its intended purpose, or in some cases even
unanticipated purposes.
• Such issues can make or break its success
even regardless of other issues.
• This involves a wide range of textual,
graphical and sometimes hardware elements
that improve the clarity, intuitiveness,
cohesiveness and completeness of a
program's user interface.

PORTABILITY
• Is the range of computer hardware and
operating system platforms on which the
source code of a program can be compiled/
interpreted and run.
• This depends on differences in the programming
facilities provided by the different platforms,
including hardware and operating system
resources, expected behavior of the hardware
and operating system, and availability of
platform specific compilers (and sometimes
libraries) for the language of the source code.

MAINTAINABILITY
• Is the ease with which a program can be
modified by its present or future developers
in order to make improvements or
customizations, fix bugs and security holes,
or adapt it to new environments.
• Good practices during initial development
make the difference in this regard.
• This quality may not be directly apparent to
the end user but it can significantly affect the
fate of a program over the long term.

METHODOLOGIES
IN
PROGRAMMING

DEBUGGING
• Debugging is a
very important
task in the
software
development
process, because
an incorrect
program can
have significant
consequences for
its users.

CONTINUATION:
• Some languages are more prone to some
kinds of faults because their specification
does not require compilers to perform as
much checking as other languages.
• Use of a static analysis tool can help detect
some possible problems
• Debugging often provide less of a visual
environment, usually using a command line.

PROGRAMMING LANGUAGES
• Different
programming
languages support
different styles of
programming
(called
programming paradigms
).

• The choice of language used is subject to many
considerations, such as company policy,
suitability to task, availability of third-party
packages, or individual preference.
• Ideally, the programming language best suited
for the task at hand will be selected. Trade-offs
from this ideal involve finding enough
programmers who know the language to build
a team, the availability of compilers for that
language, and the efficiency with which
programs written in a given language execute.
CONTINUATION:

BASIC SYNTAX IN
PROGRAMMING
LANGUAGES

INPUT
• Means - Get data
from the
keyboard, a file,
or some other
device.

OUTPUT
• Means - Display
data on the
screen or send
data to a file
or other
device.

ARITHMETIC
• Means - Perform
basic
arithmetical
operations like
addition and
multiplication.
• Also known as
COMPUTER
ALGORITHM

CONDITIONAL EXECUTION
• Means - Check
for certain
conditions and
execute the
appropriate
sequence of
statements.
• By using the
flow chart

REPETITION
• Means - Perform
some action
repeatedly,
usually with
some variation.

THE ALGORITHM
FLOW CHART

FLOW CHART
• Is a type of diagram,
that represents an
algorithm or process
, showing the steps
as boxes of various
kinds, and their
order by connecting
these with arrows.

FLOW CHART
• This diagrammatic representation can give a
step-by-step solution to a given problem.
• Data is represented in these boxes, and
arrows connecting them represent flow /
direction of flow of data.
• Flowcharts are used in analyzing, designing,
documenting or managing a process or
program in various fields

4 GENERAL TYPES FLOW CHART
• Document flowcharts, showing controls over
a document-flow through a system
• Data flowcharts, showing controls over a
data flows in a system
• System flowcharts showing controls at a
physical or resource level
• Program flowchart, showing the controls in a
program within a system

FLOW CHART SYMBOLS
The Basic Types of Flow Chart Symbols
• Start and End Symbols
• Arrows
• Processing Steps
• Input / Output
• Conditional or Decision

START AND END SYMBOLS
• Is represented as
circles, ovals or
rounded rectangles,
usually containing the
word "Start" or "End",
or another phrase
signaling the start or
end of a process, such
as "submit enquiry" or
"receive product"
END
STARTSTART

ARROW SYMBOLS
• Is showing what's
called "flow of control"
in computer science.
• An arrow coming from
one symbol and ending
at another symbol
represents that control
passes to the symbol
the arrow points to.
FLOW
OF
DIRECTION

PROCESSING SYMBOLS / STEPS
• Is Represented as
rectangles.
• It also represents
any process,
function, or action
and is the most
frequently used
symbol in
flowcharting
DO SOMETHING

INPUT AND OUTPUT SYMBOLS
• Is represented as a
parallelogram to
display the Input
and Output in
program.
INPUT
OUTPUT

CONDITIONAL OR DECISION SYMBOL
• Is represented as a
diamond (rhombus).
• These typically
contain a Yes/No
question or
True/False test.
• This symbol is
unique in that it has
two arrows coming
out of it,
DECISION

CONDITIONAL OR DECISION SYMBOL
• usually from the bottom point and right
point, one corresponding to Yes or True, and
one corresponding to No or False. The
arrows should always be labeled.
• A decision is necessary in a flowchart. More
than two arrows can be used, but this is
normally a clear indicator that a complex
decision is being taken, in which case it may
need to be broken-down further, or
replaced with the "pre-defined process"
symbol.

CONNECTOR SYMBOL
• Is represented as
circle.
• To rejoin or attach
the arrow symbol for
the flow of direction
CONNECT

EXAMPLE OF FLOWCHART PROCESS
STARTSTART
MIX THE INGREDIENTS
HOME
CONSUMPTION
ONLY
PACKAGING,
CARTONING/PALLETIZING
KNEADING, PROOFING ,
BAKING
ORDER?
STOPSTOP
Yes
No
SHIPPING / DELIVER
THE PRODUCT

TURBO C PROGRAMMING
• Turbo Basic is a
BASIC compiler and
dialect originally
created by Robert
"Bob" Zale and
bought from him
by Borland.

TURBO C PROGRAMMING
• This software is
from the 1987-
1988 period and
features the
Borland "black
screen" similar to
Turbo Pascal 4.0,
Turbo C 1.0/1.5,
and Turbo Prolog
1.1.

CONTINUATION
• Borland did not adopt its trademark "blue
screen" integrated development
environment until the 1989 period when
Turbo C 2.0, Turbo C++ 1.1, etc. were
released. By this time, Turbo Basic and
Turbo Prolog were no longer being sold.
• Unlike most BASIC implementations of this
period, Turbo Basic was a full compiler
which generated native code for MS-DOS.

TURBO C PROGRAM
SYNTAX

• Basic command list
 #INCLUDE <STDIO.H> = Standard Input / Output
 { } = Cover of programs (start and Ends)
 ; = command function at the end of message
 CLRSCR ();
 PRINTF = display message ( INPUT QUESTIONS)
 IF = (Conditional commands)
 END IF / ELSE IF = (Conditional commands)
 SCANF = scanning of output response
 DO = process
 INPUT = process
 // Display = output response after the process
 LOOP = go back to previous
 NEXT = proceed to next process
 GO TO = proceed to specific input / command
 GETCH (); = End of program

• EXAMPLE: TURBO C PROGRAM
#INCLUDE <STDIO.H>
MAIN
{
CLRSCR ();
PRINTF ("Hit any key to continue: ");
// Wait for a key press, flashing the message
// “Welcome to Marianne’s Baking Business“; on
and off once per second.
// After any key is hit, display “(Y)!" ;
// After any key is hit, display “(N)!" ;
INPUT “Y / N”;
SCANF (“Where Y = Yes, Where N = No");

IF (N);
LOOP
PRINTF "Goodbye ";
IF (Y);
// Display “First Step: Mixing of Ingredients!" ;
DO
INPUT “Mixing of Ingredients";
// Display “Image of End Product" ;
NEXT 2
INPUT “Y / N”;
IF (N);
LOOP
PRINTF "Goodbye ";

IF (Y);
// Display “Second Step: Kneading, Proofing and
Baking!" ;
DO
INPUT “Kneading, Proofing and Baking Process";
NEXT 3
INPUT “Y / N”;
IF (N);
LOOP
PRINTF "Goodbye ";
IF (Y);
// Display “Third Step: Packaging, Cartoning and
Palletizing!" ;

DO
INPUT “Packaging, Cartoning and Palletizing Process";
NEXT 4
INPUT “Y / N”;
IF (N);
LOOP
PRINTF "Goodbye ";
IF (Y);
// Display “Is there any order?";
NEXT 5
INPUT “Y / N”;

END IF (N);
// Display “For Home consumption only!";
PRINTF “Thank You for visiting our website!";
END IF (Y);
GO TO
// Display “Ready for Shipment and Delivery!";
DO
INPUT “Shipping and Delivering of Product!";
// Display “Image of Delivering Process" ;
PRINTF “Thank You for visiting our website!";
GETCH ();
}

PRESS ANY KEY TO CONTINUE
Y N

PACKAGING, CARTONING AND
PALLETIZING

SHIPPING AND DELIVERING

COMPUTER PROGRAMMING

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