This document discusses representing the logic of programs with conditions using flowcharts. It covers variables, constants, data types, operators, and decision structures. Examples are provided to demonstrate how to represent accepting input, performing calculations, and making conditional decisions in a flowchart. Key topics include declaring variables, arithmetic, relational and logical operators, and using decision boxes to apply conditions.

1. Representing the Logic of Programs with Conditions
Objectives
In this lesson, you will learn about:
Data and data types
Using operators
Representing decisions in a flowchart
©NIIT PLT/Lesson 2/Slide 1 of 33

2. Representing the Logic of Programs with Conditions
Variables and Constants
Flowchart to display the sum of two numbers
Start
Accept the
First Number
Accept the
Second Number
Add the two Numbers
and Store the Result
Display the Result
Stop
©NIIT PLT/Lesson 2/Slide 2 of 33

3. Representing the Logic of Programs with Conditions
Variables and Constants (Contd.)
The internal memory consists of different locations in
which data is stored
A computer needs to identify the memory locations to
be able to retrieve values from or store values in them
The value of a variable changes each time the set of
instructions is executed
The values stored in the variables are known as
constants
©NIIT PLT/Lesson 2/Slide 3 of 33

4. Representing the Logic of Programs with Conditions
Variables and Constants (Contd.)
Constants
10 15 25
nNum1 nNum2 nSum
Variables
©NIIT PLT/Lesson 2/Slide 4 of 33

5. Representing the Logic of Programs with Conditions
Variables and Constants (Contd.)
Flowchart to display the sum of two numbers using
variables. Start
Accept nNum1
Accept nNum2
nSum = nNum1 + nNum2
Display nSum
Stop
©NIIT PLT/Lesson 2/Slide 5 of 33

6. Representing the Logic of Programs with Conditions
Just a Minute…
Identify the variable and constant data in the following
situation:
Each day, the courier service delivers some letters. The
number of letters is different each day. Regardless of the
number of letters delivered by the courier service, they
are paid a carrying charge of $5.
Variable:
Constant:
©NIIT PLT/Lesson 2/Slide 6 of 33

7. Representing the Logic of Programs with Conditions
Just a Minute…
Identify the variables and constants from the list
given below:
a) Age
b) Address
c) 21
d) “10, Kingsway Camp”
e) “Henri”
f) Name
g) “185”
©NIIT PLT/Lesson 2/Slide 7 of 33

8. Representing the Logic of Programs with Conditions
Data Types
Numeric
Numeric variables can contain only numbers
These variables can be used in arithmetic
operations
Character
Character variables can contain any combination
of letters, numbers, and special characters
These variables cannot be used for calculation
©NIIT PLT/Lesson 2/Slide 8 of 33

9. Representing the Logic of Programs with Conditions
Data Types
Declaring Variables
Start
numeric nNum1,
nNum2, nSum
Accept nNum1
Accept nNum2
nSum = nNum1 + nNum2
Display nSum
Stop
©NIIT PLT/Lesson 2/Slide 9 of 33

10. Representing the Logic of Programs with Conditions
Data Types
Variable Naming Conventions
® Thefirst letter of the variable may indicate the
data type used
® Thevariable name should clearly describe its
purpose
® In
case of multiple words, the first letter of each
word could be capitalized for better readability
©NIIT PLT/Lesson 2/Slide 10 of 33

11. Representing the Logic of Programs with Conditions
Using Operators
Operators are tools for some predefined operations
The operators that are used in flowcharts are:
Arithmetic operators
Relational operators
Logical operators
©NIIT PLT/Lesson 2/Slide 11 of 33

12. Representing the Logic of Programs with Conditions
Using Operators
Arithmetic operators
Arithmetic operators are used to perform arithmetic
calculations
The symbols that represent arithmetic operations
are called arithmetic operators (*, /, +, -, %)
Relational operators
Relational operators are used to test the
relationship between two variables or the
relationship between a variable and a constant
There are six relational operators (=,,,!=,=,=)
©NIIT PLT/Lesson 2/Slide 12 of 33

13. Representing the Logic of Programs with Conditions
Using Operators
Logical operators
Logical operators (AND, OR, NOT) are used to
combine expressions containing relational
operators
® nNum1 = 7 AND nNum2 5
® nNum1 = 7 OR nNum2 5
® NOT nNum2 = 5
Precedence of the execution of logical operators
are NOT, AND, and OR.
©NIIT PLT/Lesson 2/Slide 13 of 33

14. Representing the Logic of Programs with Conditions
Just a Minute…
Draw a flowchart to accept item name, price, and
quantity. You need to calculate value as the product of
price and quantity, and display the calculated value and
the item name using variables.
©NIIT PLT/Lesson 2/Slide 14 of 33

15. Representing the Logic of Programs with Conditions
Representing Decisions in a Flowchart
Many problems require decisions to be made
All decisions may or may not state an action to be
taken if the condition is false
©NIIT PLT/Lesson 2/Slide 15 of 33

16. Representing the Logic of Programs with Conditions
Representing Decisions in a Flowchart
Flowchart Segment to Compare Two Numbers and
Check for Equality
Is nNum1 = No
nNum2 ?
Yes
Display “The Display “The
numbers are numbers are
equal” not equal”
©NIIT PLT/Lesson 2/Slide 16 of 33

17. Representing the Logic of Programs with Conditions
Example
Accept two numbers and print the larger of the two
numbers.
Start
numeric nNum1,
nNum2
Accept nNum1
Accept nNum2
A
©NIIT PLT/Lesson 2/Slide 17 of 33

18. Representing the Logic of Programs with Conditions
Example (Contd.)
A
Is Yes Display “ The
nNum1=nNum2? numbers are equal”
No
Is Yes
nNum1nNum2? Display nNum1
No
Display nNum2
Stop
©NIIT PLT/Lesson 2/Slide 18 of 33

19. Representing the Logic of Programs with Conditions
Example
Print the value of nX only if the value of nX is greater
than 10 and nX is an even number.
Start
numeric nX
Accept nX
Is
No
nX10 AND
nX%2=0?
Yes
Display nX
Stop
©NIIT PLT/Lesson 2/Slide 19 of 33

20. Representing the Logic of Programs with Conditions
Example
Accept the year and then determine whether the year is
a leap year or not. A leap year is one that is divisible by
4, other than a century year, such as 1900. A century
year, which is divisible by 400, such as 2000, is also a
leap year.
To evaluate the given condition, we can interpret this as:
If year is divisible by 4 AND not divisible by 100 OR
divisible by 400, it is a leap year.
©NIIT PLT/Lesson 2/Slide 20 of 33

21. Representing the Logic of Programs with Conditions
Flowchart to Determine the Leap Year
Start
numeric nYear
Display “ Please
enter a year”
Accept nYear
A
©NIIT PLT/Lesson 2/Slide 21 of 33

22. Representing the Logic of Programs with Conditions
Flowchart to Determine the Leap Year (Contd.)
A
Is
nYear % 4=0 AND No Display “ This is
(nYear % 100 !=0 OR
not a leap year”
nYear % 400=0) ?
Yes
Display “This is
a leap year”
Stop
©NIIT PLT/Lesson 2/Slide 22 of 33

23. Representing the Logic of Programs with Conditions
Example
To decide about the discount percentage on a TV, the
sales person needs to check the type of TV. If the TV is
Black and White [B], the discount will be 5 percent of the
selling price. If the type of TV is colored[C], then he has
to verify the size of TV screen. For 14 inches screen,
discount is 8 percent of the selling price and for 21
inches screen, the discount is 10 percent of the selling
price.
©NIIT PLT/Lesson 2/Slide 23 of 33

24. Representing the Logic of Programs with Conditions
Flowchart to Calculate Discount
Start
numeric nScreen, nDiscount
character cType
Accept cType
Accept
nScreen
Is Yes
cType=‘B’? nDiscount=5% of SP
No
Is Yes Is Yes
nDiscount=8% of SP
cType=‘C’? nScreen=14?
No No
Is Yes
nDiscount=10% of SP
nScreen=21?
No
Stop
©NIIT PLT/Lesson 2/Slide 24 of 33

25. Representing the Logic of Programs with Conditions
Problem Statement 2.P.1
Study the given flowchart and answer the following
questions.
What will be output when:
a) nNum=7
b) nNum=3
c) nNum=11
©NIIT PLT/Lesson 2/Slide 25 of 33

26. Representing the Logic of Programs with Conditions
Problem Statement 2.P.1(Contd.)
Start
numeric nNum
Accept nNum
Is Yes
nNum10? Display “ GOOD”
No
Is Yes
nNum5? Display “OK”
No
Display “REJECT”
Stop
©NIIT PLT/Lesson 2/Slide 26 of 33

27. Representing the Logic of Programs with Conditions
Problem Statement 2.P.2
Study the flowchart and answer the following questions.
What will be the output when:
a) nX=150 and nY=75
b) nX=90 and nY=50
c) nX=40 and nY=80
©NIIT PLT/Lesson 2/Slide 27 of 33

28. Representing the Logic of Programs with Conditions
Problem Statement 2.P.2 (Contd.)
Start
numeric nX, nY
Accept nX
Accept nY
Is Yes Is Yes
nX nY ? nX 100 ? Display “ GOOD”
No No
Is No
nY 100 ?
Yes
Display nY
Stop
©NIIT PLT/Lesson 2/Slide 28 of 33

29. Representing the Logic of Programs with Conditions
Problem Statement 2.P.3
Draw a flowchart to accept a number and then find out
whether or not the number is divisible by 5.
©NIIT PLT/Lesson 2/Slide 29 of 33

30. Representing the Logic of Programs with Conditions
Problem Statement 2.P.4
Draw a flowchart to accept three numbers and display
the largest number.
©NIIT PLT/Lesson 2/Slide 30 of 33

31. Representing the Logic of Programs with Conditions
Problem Statement 2.P.5
Candidates have to enter their age. The age cannot be
negative. If a negative age is entered, an error message
has to be displayed, otherwise the age is displayed.
Represent the error checking logic for this situation
using a flowchart.
©NIIT PLT/Lesson 2/Slide 31 of 33

32. Representing the Logic of Programs with Conditions
Summary
In this lesson, you learned that:
Data can be categorized as a constant or variable
Data types can be:
Numeric
Character
The operators are:
Arithmetic
Relational
Logical
©NIIT PLT/Lesson 2/Slide 32 of 33

33. Representing the Logic of Programs with Conditions
Summary (Contd.)
Arithmetic operators are used to perform arithmetic
calculations. The symbols that represents arithmetic
operations are called arithmetic operators (*,/,+,-,%).
Relational operators are used to test the relationship
between two variables. The symbols that represent
relational operations are called relational operators
(,,=,!=).
Logical operators (AND, OR, NOT) are used to
combine expressions containing relational operators.
The decision box is used to apply conditions by asking
a question in a flowchart.
©NIIT PLT/Lesson 2/Slide 33 of 33