Information &
Communication Technology
Lecture# 05
Introduction To Software
Design & Algorithms
Software
➢ A set of instructions that tells a computer
what to do
➢ Written computer program/Series of
instructions
➢ Software allows hardware to perform
useful work
➢ Communication between user and computer
System Software
➢ A group of programs that controls all the
operations of computer
➢ Designed to run computer hardware and
other application programs
➢ Make better and effective utilization of
entire computer system
➢ Development of compiler, OS & High Level
language
➢ System programming & system programmer
Types of system software
➢ System Management Programs
➢ Manages hardware, software & network
➢ OS, Anti Virus, Data Recovery Software etc
➢ System Support Program
➢ Support operations and management
➢ System Security, Device Drivers
➢ System Development Programs
➢ Program that help user in developing other
programs e.g programming editors (Dev-C++)
Application Software
➢ Designed for users, perform specific task for
them
➢ General Purpose Program
➢ Perform common information processing for end
users & every user can use it for own purpose
➢ E.g word, MS Access, Graphics Designing, Database
➢ Application Specific/Special Purpose
➢ Perform specific task, can not perform different
task
➢ Chrome, Auto Cad, WhatsApp, HBL Mobile App
Programming Tools
➢ With the help of which a programmer can
write a perfect program
➢ Algorithms
➢ A finite set of instructions or rules which
are followed for solving a problem
➢ Provide a base for programming
Algorithm Notation
➢ Name of Algorithm written in capital
➢ Name is followed by a brief description of
the task algorithm performs
➢ Sequence of numbered steps
➢ Beginning with a phrase enclosed in square
brackets, which is followed by a statement
which describe the action to be performed
➢ Algorithm step may terminate with a
comment
Example
➢ GRADES(M1,M2,M3,M4, Average)
➢ This algorithm reads four marks denoted
by M1,M2,M3,M4 and calculate the average
grade. All variables are assumed to be real.
➢ (1) start
➢ (2) [Declaration] int M1,M2,M3, AVG
➢ (3) [input individual marks] Read(M1,M2,M3)
➢ (4) [Average Calculation] AVG=(M1+M2+M3)/3
➢ (5) [Output Result] Write(“The average =”, AVG)
➢ (6) [Finish] Exit
Flow Charts
➢ Graphical representation of an algorithm or a portion of
algorithm
➢ Drawn using certain special-purpose symbols connected by
arrows called flow lines
➢ Special Purpose Symbol
➢ Following are some symbols to draw a flow chart and there
purpose
Oval shape indicate start or end of the
program usually containing the word "Start,
begin” or "End“.
Rectangles are processing symbols to
indicate any type of processing, including
a calculation
Flow Charts
Diamonds are conditional or decision
symbols. It indicates a decision to be
made.
Parallelogram are the input/output symbols
Arrows are called flow lines.
Indicate the flow of program.
Example
Thank You ☺
