DISE - Programming Concepts

Diploma in Software Engineering
Module II: Programming Concepts
Rasan Samarasinghe
ESOFT Computer Studies (pvt) Ltd.
No 68/1, Main Street, Pallegama, Embilipitiya.

Contents
1. What is computer programming?
2. Programming Styles
3. Unstructured Programming
4. Structured Programming
5. Object Oriented Programming
6. Computer Programs
7. Concept of Algorithm
8. Computer Programs
9. Concept of Algorithm
10. Flow Charts
11. Questions
12. Pseudo Codes

What is computer programming?
Programming is giving instructions to the
computer how to interact with the user or
perform specific task.
Within software engineering, programming is
regarded as one phase in a software
development process.

Programming Styles
There are 3 main programming styles
1. Unstructured Programming
2. Structured Programming
3. Object Oriented Programming

Unstructured Programming
• Unstructured programming is the historically
earliest programming paradigm.
• It is procedural, the statements are executed in
sequence as written.
• This type of programming uses goto statements.
A goto statement allows control to be passed to
any other place in the program.
• Difficult to understand the logic of the program.
Ex: Machine Language, COBOL

Structured Programming
• Structured programming also a subset of
procedural programming that enforces to write
efficient code easier to understand and modify.
• Use of the goto statement is discouraged.
• Structured programming using 3 controls
constructs:
– Sequence
– Selection
– repetition
Ex: Pascal, Ada

Object Oriented Programming
• Object-oriented programming (OOP) is a
programming model organized around objects
rather than actions and data rather than logic.
• It is more popular in present, because it has an
ability to represent complex relationships, data
and data processing with suitable notations.
Ex: Java, C++, C#

Computer Programs
• Sequential Processing
Instructions are performed
one after other in the
computer.
• Concurrent Processing
Instructions are performed
in parallel within the
computer.
Input x
Input y
Total = x+y
Input z
Total = total +z
Input x
Input y
Total = x+y
Input z
Total = total +z

Concept of Algorithm
• An algorithm is a set of steps for solving a
particular problem.
• Algorithm steps are unambiguous and have a
clear stopping point.
• Algorithms can be expressed in any language,
from natural languages or programming
languages.

Flow Charts
A flowchart is a diagrammatic representation
of the process involved to provide a solution
to a problem.

Flow Chart Notations
Start / End of the program
Input / Output
Process
Decision / Repetition
Flow
Connector

Flow Charts
• Question 1:
Draw a flowchart to develop a program to
input the student index number, name and
total marks scored in three modules and
display the students index number, name and
average marks on the screen.

Flow Charts
• Question 2:
input stno, name, module one marks and
module two marks and display stno, name,
avg marks and total marks.

Flow Charts
• Question 3:
A student has sat for an exam and following
details entered through the keyboard;
“student number, name and average marks”. If
he scored more than 50 as average marks he
will be graded as “pass”, otherwise graded as
“fail”. Draw a flowchart to display the student
name, average and grade.

Flow Charts
• Question 4:
Draw a flowchart to input two numbers from
the keyboard and evaluate and display the
maximum value.

Flow Charts
• Question 5:
input student no, name, module one and
module two marks by the keyboard and
display student no, average and the grade. The
grading system is as follows. Average greater
than 75 grade is “distinction”, between 50 and
75 grade is “credit”, between 25 and 50 grade
is “pass” and less than 25 is “fail”.

Flow Charts
• Question 6:
Draw a flowchart to calculate and display the
sum of first five natural numbers.

Flow Charts
• Question 7:
Draw a flowchart to input a number from
keyboard, and there after calculate and
display the factorial number of it.

Flow Charts
• Question 8:
The program has to read a file stored in the
disk in which each record contain customer
number, customer name and amount. Display
only the name of the customers who has
amount greater than 1000. Draw a flowchart
for the above scenario.

Flow Charts
• Question 9:
A program has to be developed to read a file
stored in the disk in which each record contain
employee number, name, basic salary,
allowances and deductions. Calculate and
display all employee names with their net
salary. Draw a flowchart for the above
problem.

Flow Charts
• Question 10:
stored in disk in which each record contain
employee no, name and hours worked.
Calculate and display the percentage of
employees those who has worked more than
40 hours. Draw a flowchart for the above
program.

Flow Charts
• Question 11:
stored in disk in which each record contain
student no, name, subject one marks and
subject two marks. Program is displaying two
student names who has got highest marks and
lowest marks with their total marks. Draw a
flowchart for the above program.

Pseudo Codes
Pseudo code consists of short, English phrases
used to explain specific tasks within a
program's algorithm. Pseudo code should not
include keywords in any specific computer
languages. It should be written as a list of
consecutive phrases.

Pseudo Codes
One of the concepts in programming is…
PROGRAM = DATA + ALGORITHM
Data
 Data types: String, Integer, Real
 Data usage: Variable, Constant
 Data scope: Global data, Local data
Algorithm
 Sequence
 Selection
 Repetition

The End
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DISE - Programming Concepts

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