CHAPTER 9
PSEUDOCODE AND
FLOWCHARTS
LEARNING OBJECTIVE: STUDENT WILL LEARN HOW TO CREATE PSEUDOCODE.
• COMPUTER SYSTEM
Computer System : A COMPUTER SYSTEM is made up of
software, data, hardware, communications and people;
each computer system can be divided up into a set of sub-systems.
Ex: Alarm app for Smart Phone etc…..
TASK 1
IDENTIFY AT LEAST FIVE COMPUTER SYSTEMS
YOU FREQUENTLY USE IN YOUR DAILY LIFE.
SEE IF YOU CAN DECIDE THE SIZE OF EACH
SYSTEM.
TOP-DOWN DESIGN
• TOP-DOWN DESIGN is the breaking down of a computer system into a set
of subsystems, then breaking each sub-system down into a set of smaller
sub-systems, until each sub-system just performs a single action.
• In order to show top-down design in a diagrammatic form, structure
diagrams can be used.
LIBRARY ROUTINE
A LIBRARY ROUTINE is a set of programming instructions for a
given task that is already available for use. It is pre-tested and
usually performs a task that is frequently required.
Ex: import <math.h>, import <String.h>
SUB-ROUTINE(PROGRAM)
• A SUB-ROUTINE is a set of programming instructions for a given task that forms
a subsystem, not the whole system. Sub-routines written in high-level
programming languages are called ‘procedures’ and
‘functions’ depending on how they are used.
ALGORITHM: AN ALGORITHM SETS OUT THE
STEPS TO COMPLETE A GIVEN TASK.
• ALGORITHM CAN BE WRITTEN AS PSEUDOCODE OR FLOWCHART.
• PSEUDOCODE: PSEUDOCODE is a simple method
of showing an algorithm, using English-like words
and mathematical operators that are set out to look
like a program.
Algorithm
Step1: enter the numbers
Step2:use mathematical
operator+ for adding
numbers
Step3:print the calculation
Pseudocode:
DECLARE Num1,Num2,Sum As INTEGERS
INPUT “Enter num1”, Num1
INPUT “Enter num2”, Num2
Sum= Num1+Num2
PRINT Sum
PSEUDOCODE
• It is used to dry run to check whether the programs run properly or not.
MATH OPERATORS
3^4=3*3*3*3
RELATIONAL OPERATORS
• Relational operations The following symbols are used for relational operators
(also known as comparison operators):
1. > Greater than
2. < Less than
3. >= Greater than or equal to
4. <= Less than or equal to
5. = Equal to
6.
<> Not equal to
LOGICAL OPERATOR
• AND
both
• OR
either
• NOT
not
DATA TYPES
• Integer: a whole number e.g. 4, -9
• Real: a number capable of containing a fractional part
• e.g. 5.6, 3.98, 1.001,0.8
• Char: a single character
• e.g. ‘h’ , ‘C’
• String: A sequence of zero or more characters
• e.g. “This is string”
• Boolean: The logical values TRUE and FALSE
• Date: entering Date
COST
PRICECOST
30
ASSIGNMENT
30
• Values are assigned to a variable using the ‘ ← ‘operator.
The variable on the left of the ← is assigned the value of
the expression on the right.
• Cost ← 30
• Price ← Cost
-Cost has the value 30

• Tax ← Price * 0.12
• SellingPrice ← Price + Tax
Cost
30
Price
-Price = 30
-Price = 30
-SellingPrice = 23.6
cost
30
TASK TO BE DONE IN CLASS
• Task1: Write the pseudocode to find the selling price of car if the cost price is
110000 AED and 25% TAX.
• COSTPRICE110000
• TAX(25/100)*COSTPRICE
• SELLINGPRICE COSTPRICE+TAX
• PRINT SELLINGPRICE
• Task 2: Write the python program for the same.
INPUT AND OUTPUT STATEMENTS IN
PSEUDOCODE
Plenary
FLOW CHART
ALARM APP
FLOW CHART
A flowchart can also be defined as a diagrammatic
representation of an algorithm, a step-by-step
approach for solving a task.
COMPARING TWO NUMBERS
• TASK1 : Draw the Flow Chart to Compare two Numbers
DRAW THE FLOWCHART AND WRITE
PSEUDOCODE
• If the temperature of the DAY is greater than
23 degrees than display HOT started else
Display its COLD.