FLOWCHART
Flowcharting is a tool for analyzing processes. It allows you to break any
process down into individual events or activities and to display these in
shorthand form showing the logical relationships between them.
Constructing flowcharts promotes better understanding of processes,
and better understanding of processes is a pre-requisite for
improvement.
Examples of processes are "Receiving orders and entering them into
the computer system" or "Converting dry-mix powder into tablet form"
or "Following-up sales enquiries". The events which make up a process,
and which appear in the flowchart, may be of any type. For example,
they may be "taking a phone call", "completing an order form", "printing a
report", "deciding between a number of alternatives", and so on. The
symbols used to represent each event may take any form. They may be
boxes, circles, diamonds or other shapes, or events may simply be
described in words. Connections between events are always
represented by lines; usually with arrowheads to show the direction or
order in which they occur. These lines represent the flow of activity in
the process being described; hence the name of the technique. (See
the example in the `How to use it' section of this document.)
There are specialized applications for flowcharting (such as in computer
systems design and programming, engineering, and science) which use
standardized sets of symbols. You must decide for yourself whether these
need to be used in your particular management application. In most
circumstances these will either not be necessary or you can rely on three or
four simple symbols to cover most types of events. A useful set of symbols
is given in the `How to use it' section below. For special standardized
symbols, see the `Other references' section of this document for sources
you can refer to.
The flowchart is a means of visually presenting the flow of data
through an information processing systems, the operations performed
within the system and the sequence in which they are performed. In
this lesson, we shall concern ourselves with the program flowchart,
which describes what operations (and in what sequence) are required
to solve a given problem. The program flowchart can be likened to the
blueprint of a building. As we know a designer draws a blueprint before
starting construction on a building. Similarly, a programmer prefers to
draw a flowchart prior to writing a computer program. As in the case
of the drawing of a blueprint, the flowchart is drawn according to
defined rules and using standard flowchart symbols prescribed by the
American National Standard Institute, Inc.
The flowchart is a means of visually presenting the flow of data
through an information processing systems, the operations
performed within the system and the sequence in which they are
performed. In this lesson, we shall concern ourselves with the
program flowchart, which describes what operations (and in what
sequence) are required to solve a given problem. The program
flowchart can be likened to the blueprint of a building. As we
know a designer draws a blueprint before starting construction on
a building. Similarly, a programmer prefers to draw a flowchart
prior to writing a computer program. As in the case of the
drawing of a blueprint, the flowchart is drawn according to
defined rules and using standard flowchart symbols prescribed by
the American National Standard Institute, Inc.
Flowcharts are used to make decisions on the development and
flow of a program on macro, meso and micro levels.
It is a clear graphic representation of a process from beginning to
end, regardless of whether that process is an algorithm or a
manufacturing procedure.
- Flowcharts are the most commonly used graphic method of
describing computer operations. Their major uses are in the
documentation and in programming. As a documentation tool a
flowchart helps you understand the nature of computer operation,
regardless of the programming language or the computer used. In
program development, the programmer uses flowcharting in every
parts of his work to:
•Organize facts and ideas on paper.
•Define the problems and the show solutions.
•Deal systematically with the problem as a whole.
•Build his own reference documentation and reminders in a stepby-step fashion
Imagine that you are an engineer. For you the flowchart is like a
blueprint or a house. Using a blueprint, you can specify the type of
materials needed. You can easily tell the location of the kitchen and of
the bathroom. The blueprint also gives you directions as to which part
of the structure should be built first.
In programming, a flowchart is an all-purpose tool. It is the
“blueprint” of a program, while you are still in the development stage.
Flowcharts are useful tools when improving a process, especially when
you are planning to connect data or to implement a solution. They can
be also used to document a new process or to compare an existing one
with the ‘ideal’. You ca try out various approaches in laying out the
program flow or logic. Because flowcharts use graphic representations
of the procedures, they can tell us
a lot about the process and the activities involved. We can easily see
the relationships of the broad concepts and the minor details of the
data flow. Flowcharts are important when figuring out complicated
steps in programming.
FLOWCHART
SYMBOLS
A set of useful standard symbols
It is not strictly necessary to use boxes, circles, diamonds or other such symbols
to construct a flowchart, but these do help to describe the types of events in
the chart more clearly. Described below are a set of standard symbols which are
applicable to most situations without being overly complex.
Rounded box - use it to represent an event which occurs
automatically. Such an event will trigger a subsequent
action, for example `receive telephone call’, or describe a
new state of affairs.
Rectangle or box - use it to represent an event which is
controlled within the process. Typically this will be a step or
action which is taken. In most flowcharts this will be the most
frequently used symbol.
Diamond - use it to represent a decision point in the
process. Typically, the statement in the symbol will require
a `yes' or `no' response and branch to different parts of
the flowchart accordingly.
Circle - use it to represent a point at which the flowchart
connects with another process. The name or reference for the
other process should appear within the symbol.
When dealing with a process flow chart, two separate stages of the
process should be considered: the finished product and the making of
the product. In order to analyze the finished product or how to
operate the process, flow charts tend to use simple and easily
recognizable symbols. The basic flow chart symbols below are used
when analyzing how to operate a process.
In order to analyze the second condition for a flow process chart, one
should use the ANSI standard symbols. The ANSI standard symbols
used most often include the following:
Drive Nail, Cement, Type Letter.
Move Material by truck, conveyor, or hand.
Raw Material in bins, finished product on pallets, or
filed documents.
Wait for elevator, papers waiting, material waiting
Read gages, read papers for information, or
check quality of goods.
Any combination of two or more of these symbols
show an understanding for a joint process.
Action or Process A box can represent a single
step ("add two cups of flour"), or and entire subprocess ("make bread") within a larger process.
Document
A printed document or report.
Decision A decision or branching point. Lines
representing different decisions emerge from
different points of the diamond.
Input/Output Represents material or information
entering or leaving the system, such as customer
order (input) or a product (output).
Connector Indicates that the flow continues where a
matching symbol (containing the same letter) has been
placed.
Flow Line Lines indicate the sequence of steps and the
direction of flow.
Delay Indicates a delay in the process.
Merge Indicates a step where two or more sub-lists or subprocesses become one.
Collate Indicates a step that orders information into a
standard format.
Sort Indicates a step that organizes a list of items into a
sequence or sets based on some pre-determined criteria.
Subroutine Indicates a sequence of actions that perform
a specific task embedded within a larger process. This
sequence of actions could be described in more detail on
a separate flowchart.
Manual Loop Indicates a sequence of commands that will
continue to repeat until stopped manually.
Loop Limit Indicates the point at which a loop should stop.
Data storage Indicates a step where data gets stored.
Database Indicates a list of information with a standard
structure that
Display Indicates a step that displays information.
Off Page Indicates that the process continues off page.
Terminal Is used to start and end a flowchart.
FLOWCHART
TECHNIQUES
Flow Chart Technique
Primary Purpose
The flow chart technique is used to show the sequential
actions and decisions in a complex process. It reduces complexity by
showing a likely set of actions and simple decisions.
Sources / Resource(s) / Reference(s)
Carlisle, K. E. (1986) . Analyzing Jobs and Tasks.
Englewood Cliffs, NJ: Educational Technology
Publications, Inc.
Special Comments and Caveats
* The Flow Chart Technique is relatively simple to use and produces a
very clear and understandable task description. Alternative actions
are shown as sequential steps. This method is reasonable time
efficient.
* Jobs with many options decisions are not handled easily with the
Flow Chart Technique.
The ability of the computer to fetch and execute instructions
repeatedly, accurately and at very high speed coupled with its ability to
make decision on alternative processing makes the computer appears to
be a powerful device. The programmer writes code in a programming
language that specifies what instruction is to be executed in a program.
The kind of processing done by the basic control elements that
determine branching during the sequence of program statement
execution can be described as:
1. Alternative processing or
2.. Repetitive processing
Actually, both type of processing is base on a process of decision
making. The difference is that the control path in one case does not
lead to a repeat of processing done before. Alternative processing in a
program is implemented using the control logic known as the case
structure or the comparing logic structure. Loops are implemented
using the loop logic structure.
TYPES OF
FLOWCHART
Program Flowchart
- shows the sequence of instructions in a program or
subroutine. These instructions are followed to procedure the
needed output.
START
INPUT
PROCESS
OUTPUT
DECISIO
N
END
SYSTEM FLOWCHART
- shows how the data flows from source documents through the
computer to its final distribution to the users. System flowcharts
portray the interaction among data, hardware and personnel.
SCREE
N
TAPE
CPU
PRINTER
DISK
SAMPLE PROBLEM
IN
FLOWCHARTING
Draw a flowchart to find the sum of first 50 natural numbers.
Draw a flowchart to find the largest of three numbers A, B, and C.
Draw a flowchart for computing factorial N (N!)
Where N! = 1 ´ 2 ´ 3 ´ …… N.