The document introduces algorithms in computer programming, highlighting their step-by-step logic and representation forms such as pseudocode and flowcharts. It outlines basic flowchart symbols, including terminals, input/output operations, and processes, along with examples and advantages/disadvantages of using flowcharts and pseudocode for programming. Additionally, it provides specific examples for writing pseudocode and creating flowcharts for simple mathematical operations.

1. Intro to Computer programming
for data sciences

2. Algorithm
• Term algorithm is often used to refer to logic of a
program
• Step by step description how to arrive at solution
• Written in English language
Each instruction should be precise & unambiguous
Each instruction should complete in finite time
Instructions should not be repeated infinitely
After algorithm termination, desired result must be
obtained

3. Algorithms - Representation
• How are the Algorithms developed and
represented?
• Answer:
– Pseudocodes
– Flow chart
– Programs
•When an algorithm is represented in form of
programming languages, it becomes a
program
•When an algorithm is represented in form of
graphical representation, it becomes flow
chart
•When an algorithm is represented in form of
informal language, it becomes pseudocode

4. Algorithms – Pseudo code and Flow Chart
– Psuedocode
○Artificial, informal language.
○Analysis tool which is used for planning program logic
○Example: passing grade on an examination is 60.
○Pseudocode statement :
If student’s grade is greator than or equal to 60
Print “Passed”
– Flow chart
○Graphical Representation of an algorithm
○Use symbols

5. What is a Flowchart?
• Pictorial representation of
an algorithm
• A flowchart is a diagram
that depicts the “flow” of a
program.
START
Display message
“How many
hours did you
work?”
Read Hours
Display message
“How much do
you get paid per
hour?”
Read Pay Rate
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Display Gross
Pay
END

6. Flow Chart - Conventions
• Flow
– Horizontal – Left to right approach
– Vertical – Top to bottom approach
• Use of arrows
– Flow lines
• Crossing of flow lines
• Joining of flow lines
• Use of Connector

7. Basic Flowchart Symbols
• There are three types
of symbols in this
flowchart:
– rounded rectangles
– parallelograms
– a rectangle
• Each symbol represents
a different type of
operation.
START
Display message
“How many
hours did you
work?”
Read Hours
Display message
“How much do
you get paid per
hour?”
Read Pay Rate
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Display Gross
Pay
END
Rounded
Rectangle
Parallelogram
Rectangle
Rounded
Rectangle

8. Basic Flowchart Symbols
• Terminals
– indicate a starting or
ending point
START
Display message
“How many
hours did you
work?”
Read Hours
Display message
“How much do
you get paid per
hour?”
Read Pay Rate
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Display Gross
Pay
END
Terminal
START
END Terminal

9. Basic Flowchart Symbols
• Input/Output Operations
– represented by
parallelograms
– indicate an input or
output operation
START
Display message
“How many
hours did you
work?”
Read Hours
Display message
“How much do
you get paid per
hour?”
Read Pay Rate
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Display Gross
Pay
END
Display message
“How many
hours did you
work?”
Read Hours
Input/Output
Operation

10. Basic Flowchart Symbols
• Processes
– represented by rectangles
– indicates a process such as
a mathematical
computation or variable
assignment
START
Display message
“How many
hours did you
work?”
Read Hours
Display message
“How much do
you get paid per
hour?”
Read Pay Rate
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Display Gross
Pay
END
Multiply Hours
by Pay Rate.
Store result in
Gross Pay.
Process

11. Flowchart & pseudo Code
Start
get radius, PI
circumference = 2 * Pi* radius
area=PI * radius * radius
display circumference, area
End
START
Get Radius
Multiply radius
with PI and 2
to get
circumference
END
Multiply radius
with radius and
PI to get area
Display
circumference
and area
Display message
“Enter Radius:”

12. pseudo code and flow charts
Finding multiplication of two
numbers
Start
get num1, num2
product= num1*num2
display product
End
START
Get num1
END
Product=num1*num2
Display product
Get num2

13. Advantages & Disadvantages of Flow charts
Advantages
• Better communication
• Proper program documentation
• Efficient coding
• Systematic debugging
• Systematic Testing
Disadvantages
 Stretch onto several pages
 Not easy to modify
 Time consuming
 The program is likely to be unnecessary long.

14. Advantages & Disadvantages of pseudo code
• Advantages
– Converting a pseudo code is easier than
flowcharting
– Easier to modify
– Less time
• Disadvantages
– No graphical representation
– Communication problem- no standard rule
– More difficult to follow logic of pseudo code

15. 1. Obtain two numbers from the user and prints their
sum, product, difference, quotient and remainder.
2. Calculate area of a rectangle as per formula shown
(area = base * height). The base and height will be input
by the user.
3. Find ‘no. of minutes’ and ‘no. of seconds’ from a given
‘no. of hours’. User will provide hours as input.
Write pseudo code and draw flow chart of the
following programs: