This document discusses algorithms and their role in computer science. It begins by stating the goals of understanding algorithms, their development and evaluation. It then defines an algorithm as a well-developed, organized approach to solving complex problems and describes their key characteristics. The document outlines the process for developing an algorithm, including identifying inputs, outputs, processes and breaking the solution into steps. It provides examples of algorithms and flowcharts to illustrate these concepts.

2. Goals
By the end of this lecture you should …
Understand the role of a computer as a tool in
Computer Science.
Understand the study of algorithms.
Be able to identify how algorithms are developed &
evaluated.
Flowcharts

3. The Computer as a Tool
Much like the microscope does not define biology or
the test tube does not define chemistry, the computer
doesn't define Computer Science.
The computer is a tool by which Computer Scientists
accomplish their goals – to solve problems.

4. What is Computer Science?
NOT about coding or hardware or software!
Computer Science is about PROBLEM SOLVING
Computer Science is about DEVELOPING
ALGORITHMS to solve complex problems

6. What is an Algorithm?
An algorithm is a well-developed, organized approach
to solving a complex problem.
It refers to the logic of the program .
It is step by step solution to given problem.

7. Now a Create Algorithm!!
Problem: Dad said you to buy books from a shop
10km from your house.
Step 1: GET THE NAME OF BOOK
STEP2: GET MONEY FROM DAD
STEP 3: GET THE ADDRESS OF THE SHOP
STEP4: TAKE BUS TO SHOP
STEP 5: SEARCH FOR THE BOOK IN SHOP
STEP 6: BUY THE BOOK FROM SHOPKEEPER
STEP 7: COME BACK TO HOME

8. Algorithm Characteristics
Precise and unambiguous
Each instruction should be executed in finite time.
Should not repeat loop for infinite.
Correct output.

9. Developing an Algorithm
1. Identify inputs to the system.
2. Identify output of the system.
3. Identify the process.
4. Break the solution to steps.

10. 1. Identify the Inputs
What data do I need?
How will I get the data?
In what format will the data be?

11. 2. Identify the Outputs
What outputs do I need to return to the user?
What format should the outputs take?

12. 3. Identify the Processes
How can I manipulate data to produce meaningful
results?
Data vs. Information

13. 4. Break the Solution to steps.
By breaking the solution to the steps we can easily
understand the logic of program

14. Create a program to get name and
roll number from user and print it!
Step 1: Initialize name as character and roll number as
integer
Step2: Display message “ENTER NAME:” on screen
Step 3: GET NAME FROM USER
STEP 4: Display message “ENTER R.NO:”
Step 5: GET Roll number from USER
STEP 6: CLEAR THE SCREEN
STEP 7: PRINT NAME on SCREEN
STEP 8: PRINT ROLL NUMBER on SCREEN
STEP 9: STOP

15. NOW WHAT IS FLOW CHART??

16. Flow Chart
Flow Chart is pictorial representation of an
algorithm.
Whatever we have done in algorithm we can
represent it in picture.
It is easy to understand.
Shows the flow of the instruction

17. FLOW CHART SYMBOLS
/output operations

18. Example:1

19. Example 2: ADD 2 INTEGERS
START
INPUT VALUE OF A
and B
SUM=A+B
PRINT :SUM
STOP

20. Any questions?

21. Thank You