1. ALGORITHMS & FLOWCHART BASIC INTRODUCTORY COURSE

2. A PROCEDURE AN ALGORITHM
A procedure is a finite sequence of well-defined instructions
A PROCEDURE
An algorithm is a step-by-step procedure to solve a given problem
AN ALGORITHM

3. ALGORITHMS EXAMPLES OF An algorithm for preparing breakfast
An algorithm for drawing a curve
An algorithm for baking cake
An algorithm for preparing rice and stew

4. : IN REAL LIFE ALGORITHM Problem Solution Baking a Cake Start
Preheat oven at 180℃
Prepare a baking pan
Beat butter with sugar
Mix them with flour, eggs and essence vanilla
Pour the dough into a baking pan
Put the pan into the oven
End

5. ALGORITHMS? WHY DO WE BUILD
If we wish to build a house, we need to design it first.
Can you think of some possible consequences of not designing a house before building it?
Similarly, computer programs (especially large and complex ones) need to be designed before they are written.
Can you think of some possible consequences of not designing a program before building it?
One of the things considered when designing a computer program is the algorithm which it will be based on.

6. ALGORITHMS IN PROGRAM DESIGN
A computer program is built to solve a certain problem.
Examples:
A program to calculate the grades obtained in a given class
A program to produce a
document
3. A program to view an image

7. TO BUILD A PROGRAM TO SOLVE A PROBLEM?
ALGORITHM
Analyze the problem
Design a computer solution to the problem by developing an algorithm.
Write a computer program based on the algorithm.
Test the program.

8. ALGORITHM HOW TO SPECIFY AN TEXTUALLY GRAPHICALLY
For example, using pseudo code (see later)
TEXTUALLY
For example, using flowcharts or UML activity charts
GRAPHICALLY

9. FLOWCHARTS
A flowchart is a graphical representation of the sequence of operations in a program.
An algorithm can be represented graphically using a flowchart.
A flowchart is a graphical representation of an algorithm.

10. NOTATION FLOWCHARTS SYMBOL SEMANTIC Start/End Process Input/Output
Test
Connector
Flow of activities

11. FLOWCHART : EXAMPLE 1 Algorithm starts here Input data from user
Gregorian date
Input data from user
Convert Gregorian
date to Islamic date
Perform date conversion
Display
Islamic date
Display the results
End
Algorithm ends here

12. PSEUDOCODE
An outline of a program, written in a form that can easily be converted into real programming statements. It resembles the actual program that will be implemented later. However, it cannot be compiled nor executed.

13. PSEUDOCODE Pseudocode normally codes the following actions:
Initialization of variables
Assignment of values to the variables
Arithmetic operations
Relational operations

14. EXAMPLES PSEUDOCODE Start Read quantity. Read price_per_kg
price = quantity * price_per_kg
Print price
End

15. FLOWCHART : EXAMPLE 2
Start
length, width and area are referred to as variables.
A variable is like a box in which a value can be stored
Input
length,width
area length x width
Output
area
End

18. ASSIGNMENT
Write a simple algorithm for withdrawing a sum of money at an ATM.
Draw a flowchart which represents the algorithm built in above.

19. KNOW YOU SHOULD NOW What an algorithm is
When an algorithm should be developed when building a computer program
The basic steps in building a computer program to solve a problem
What flowcharts are
How to represent algorithms graphically using flowcharts

20. YOU!
THANK
END OF SESSION
COMPUTER SCIENCE AFRICA