ECE 3561 - Lecture 1 1

L8:Flowcharting a program

Department of Electrical and Computer EngineeringThe Ohio State University

ECE 2560

Flowcharting

Where does flowcharting come in?Flowcharting symbols and examplesFlowcharting a program

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What is flowcharting

Flowcharting is a method of documenting an algorithm or method for performing a sequence of actions.

Could be something that is not intended for a computer program.

Provides a graphical view of the process or method.

For assembler language can even indicate register and memory usage

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Flowcharting symbols

Straight action (or code sequence)

Enclosed in a box – sequence of code goes in the box.

Example – exchange 2 items A - -> Temp B - -> A Temp - -> B

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Flowcharting symbols

Decision structure

Example dec I jge yes Code for false branch jmp after yes Code for true branch after code that follows structure

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Flowcharting loops

A for loopFor I = 1 to 10 Loop code in loopEnd loop;

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Flowchart for a problem

We considered multiply routine (note: different register numbers used here)

Note symbol for subroutine and enter/return

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Other flowchart symbols

Have seem actions, decision, subprocess, enter/return

A couple of others that are often used

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Flowchart hierarcy

Flowchart can be written such that what is in the action (process) box is a high level statement.

The high level statement can be a program in and of itself

ORA flowchart can be done indicating

assembler instructions and which registers are used.

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