final topic (algorithms & flowcharts)

8/12/2019 final topic (Algorithms & Flowcharts)

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Algorithms & Flowcharts

Algorithm – is a list of instructions for carrying out some

process step by step. In the same way, algorithm executed by a

computer can combine millions of elementary steps, such as

additions, and subtractions, into a complicated mathematical

calculation.Example

1+1 = 2 One plus one is equal to two




Flowchart is a diagram representing the logical

sequence in which a combination of steps or operations is to

be performed. It is consists of labeled geometrical symbols

that are interconnected to provide a pictorial representationof a data processing procedure.

To the programmer, a flowchart is a kind of an all-purpose

tool. In is the “blueprint” of a program.




Advantages And Limitations Of Flowcharts

Advantages:

1. Since flowcharts are language-independent, they can belearned and applied without formal knowledge of a

programming language.

2. It enforces users to give attention to significant matters

over the less significant ones.

3. Being graphically portrayed, flowcharts provide analternative to the usual narrative description of a system or

a program.

4. Flowcharts are easier to understand than a program

written in a particular programming language.




Advantages And Limitations Of Flowcharts

Limitations:

1. Flowcharts do not represent a programming language and

are more of a person-to-person than a person-to-computer

means of communication. A computer cannot accept aprogram described in flowcharting form.

2. Since thinking in graphic terms is not normal, flowcharts

cannot be viewed as a natural means of communication.

3. Certain details often require a long sequence of

interconnected symbols which could easily be described in just a few lines of explanation.

4. It does not convey why a given set of operations is made.

Flowchart charts only portray how.

5. Flowcharts do not highlight the important details since each

step receives as much attention in a flowchart as any other.




Types Of Flowcharts The major types of flowcharts are the program and the system

flowcharts:

1. Program Flowchart – A program flowchart describesgraphically in detail the logical operations and steps within

a program and the sequence in which these steps are to be

executed for the transformation of data to produce the

needed output.

2. System Flowchart – a system flowchart is a graphicrepresentation of the procedures involved in converting

data on input media to data in output form.




Flowcharting Symbols The given symbols conform to the International Organization

for Standardization (ISO), and American National Standard.

1. Input/Output Symbols (Parallelogram) – the input / outputsymbols represents an instruction to an input or output device.

2. Processing Symbols (Rectangle) – this symbol is used to

represent a group of program instructions that perform a

processing function of the program such as to perform

arithmetic operations, or to compare, sort, etc.






3. Decision Symbol (Diamond) – this diamond-shaped boxdenotes a point in the program where more than one path can

be taken. It is used to document points in the program where,

based upon variables condition, a branch to alternative paths is

possible.

4. Preparation Symbol (Hexagon) – this symbol is used to

represent an instruction of group of instructions that will alter, or

modify a program’s course of execution.






5. Terminal Symbol (Oval) – the terminal symbol is used todesignate the beginning and the end of the program, or point of

interruption.

6. Predefined Process Symbol (Rectangle with two Vertical

Bars) – this symbol is a specialized process symbol that

represents a name operation of programmed step not explicitly

detailed in the program flowchart.






7. On-page Connector (Small Circle) – this is a noprocessing symbol which is used to connect one part of a

flowchart to another without drawing lines.

8. Flow Direction Indicators ( Arrowheads) – are used to

show the direction of processing of data flow.






9. Off-page Connector (Small Pentagon) – this type ofconnector is used instead of the on-page connector to

designate entry to or exit from a page when a flowchart

requires more than one page.

10. Flow lines ( Horizontal / Vertical lines). – flow lines are

used to show reading order or sequence in which flowchart

symbols are to be read.




start

Go to work

Take a coffee

break

Is it

time to

go

home?

Is the

boss

looking

?

Y

N

Go Home

end

N A

A

Y

Do Some WorkB

B

final topic (algorithms & flowcharts)

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