Lesson Notes By Weeks and Term - Senior Secondary School 2

SUBJECT: DATA PROCESSING

CLASS:� SS 2

DATE:

TERM: 2nd TERM

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WEEK 8

TOPIC: ALGORITMS AND FLOWCHARTS

Algorithm is the step by step procedure of solving a particular problem. It is simply a sequence of clear and precise instructions for solving a particular problem. Algorithms are usually written in English and some few mathematical notations (signs, symbols)

Characteristics of Algorithms

1. They are written in sequence.
2. They are written in English like statements.
3. Finite, it must have a beginning and an end.
4. Should be effective
5. Should not be ambiguous. Should be consistent.

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Example

An algorithm to calculate average of three numbers:

Step1: Enter the first number N1

Step2: Enter the second number N2

Step3: Enter the third number N3

Step4: Calculate the total (N1+N2+N3)

Step5: Calculate the average (N1+N2+N3)/3

Step6: Print total

Step7: Print Average

Step8: End

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Flowcharts

The flowchart is the diagrammatic representation of an algorithm. It shows the steps involved in solving a particular task.

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Characteristics of flowchart

Different flowcharting symbols are used for different operations

Flow lines are used to connect the flowcharting symbols.

Flowcharts are read and drawn from top to bottom.

The start symbol indicates the beginning of a program.

The end symbol signifies the end of a program.

Flowchart symbols:

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Process

Terminator

Flow line

Decision (control)

Input/output

Connector

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Pre-defined process/declaration

Preparation

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Reading Assignment: Reading Assignment:�

Hiit @ School, Computer Studies for Senior Secondary Education. Pgs 108 - 109

WEEKEND ASSIGNMENT

OBJECTIVE

1. _________ is the step by step procedure of solving a particular problem.

1. Problem ��� b. sequence��� c. algorithm ��� d. symbol

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2. _________ is the diagrammatic representation of a step by step procedure of solving a particular problem.

1. Algorithm��� b. Program��� c. Flowchart ��� d. sequential solution

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3. The following are characteristic of a flowchart EXCEPT one

1. Flowcharts are read and drawn from bottom to top��� b. Flowcharts end symbol signifies the end of a program��� c. Flow line are used to connect the flowchart symbols����������

1. Different flowchart symbols are used for different operation.

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4. � � � � � � The flowchart symbol represents _____________

1. Pre-define��� b. Decision��� c. Input��� ��� d. Processing

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5. The following are characteristic of an algorithm EXCEPT one
6. They are written in sequence b. An algorithm should be effective c. It must be ambiguous and inconsistent��� ��� d. They are written in English like statement

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THEORY

1. Define algorithm and flowchart

1. �State three characteristics of an algorithm

1. Write an algorithm that will compute the average of three numbers a, b, c.

1. Draw a flow chart to calculate the area of a triangle with base, b and height, h.