Flow Charts
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Basic Flow Chart Symbols
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Description of each symbols
Few sample flowcharts
Rules
An example
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Basic Flow Chart Symbol
Terminal
Decision
Input/Output
Flow lines
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Processing
Connectors
Terminal
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The terminal symbol is used to indicate the beginning
(start ), end ( stop), and pauses ( Half) in the program logic flow .
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A pause is normally used in the program logic under some error
conditions, or if forms had to be changed in the computer’s line
printer during the processing of that program.
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Input/Output
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The input / output symbol is used to denote any function of an
input / output device in the program.
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If there is a program instruction to input data from a disk, tape
,terminal, or any other type of input device , that step will be
indicated in the flowchart with an input / output symbol
similarly, all output instruction whether it is output on a printer,
magnetic tape, magnetic disk, terminal screen, or any output
device, are indicated in the flowchart with an input / output
symbol.
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Processing
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A processing symbol is used in a flowchart to represent
arithmetic and data movement instruction.
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Hence, all arithmetic processes of adding subtracting ,
multiplying and dividing are shown by a processing symbol. .
The logical process of moving data from one location of the
main memory to another is also denoted by this symbol . When
more than one arithmetic and data movement instructions are to
be executed consecutively, they are normally placed in the same
processing box and they are assumed to be executed in the order
of their appearance .
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Decision
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The decision symbol is used in a flowchart to indicate a point at which a
decision has to be made, and a branch to one of two or more alternative
points is possible.
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Figure 11.2 (see book) shows three different ways in which a decision symbol
can be used. It may be noted from these examples that the criterion for
making the decision should be indicated clearly within the decision box.
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Moreover, the condition upon which each of the possible exit paths will be
executed should be unidentified, and all the possible paths should be
accounted for.
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During execution, the appropriate path is followed depending upon the
result of the decision.
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Flow Lines
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Flow lines with arrowheads are used to indicated the flow of operation, that
is, the exact sequence in which the instructions are to be executed.
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The normal flow of flowchart is from top to bottom and left to right.
Arrowheads are required only when the normal top to flow is not to be
followed. However, as a good practice, and to avoid ambiguity, flow lines are
usually drawn with an arrowhead at the point of entry to a symbol.
Good practice also dictates that flow lines should not cross each other, and
that such intersections should be avoided whenever possible.
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Connectors
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Whenever a flowchart becomes complex enough that the
number and direction of flow lines is confusing , or it spreads
over more than one page, it is useful to utilize the connector
symbol as a substitute for flow lines.
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This symbol represents an entry from, or an exit to another part
of the flowchart.
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A connector symbol is represented by a circle, and a letter or
digit is placed within the circle to indicate the link.
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How to draw Flow Chart?
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Flow Chart Rules
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Some of the rules and guide lines are as follows:
 First chart the main line of logic
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Then incorporate detail.
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Maintain a consistent level of detail for a given flowchart.
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Do not chart every details; otherwise, the flowchart will only be a graphic
representation of the program.
Details in the flowchart should be easy for anyone to understand.
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An example
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Example: A student appears in an examination, which consists
of total 10 subjects, each subjects having maximums marks of
100. The roll number of the student, his/her name, and the
marks obtained by him/her in various subjects, are supplied as
input data. Such a collection of related data items, which is
treated as a unit, is known as a record. Draw a flowchart for the
algorithm to calculate the percentage marks obtained by the
student in this examination, and to print it along with his/her
roll number and name.
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Solution
Start
Read input
data
Add marks of all
Subjects
Giving total
Percentage =
Total/10
Write output
data
Stop
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