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Video Title: Function Point
Description: Function Point
Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm
Lecture By: Mr. Arnab Chakraborty, Tutorials Point India Private Limited
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In this session, we are discussing a very
important topic that is our function point.

So, it is widely used to measure the size
of the software.

So, function point is the way with the
help of which

you can calculate the respective size
of the software.

Function point concentrates on the
functionality provided by the system.

So, features and functionality of the
system are used to measure the respective

software complexity.

If the features are more, if the
functionalities are more, then obviously,

the software will be more complex.

Function point counts on 5 parameters.

So, we should carefully listen this one.

So, function point counts 5 parameters.

And they are named as external input,
external output, logical internal files,

external interface files and the external
inquiry.

So, these are the 5 parameters which will
be counted here.

And to consider the complexity of the
software, each parameter is divided into 3

different categories that is the simple,
average and complex.

So, here we are having 3 categories.

Here we are having 5 parameters.

So, in this particular diagram,
we have explained that one.

So, let us see these parameters of
function point.

The first one is the external input.

So, this is the point number 1.

This is our system boundary.

This is the software
program and this is the

point number 1 that
is the external input.

Next one is the external output.

So, external output will be coming out
from the software program.

That That is the point number 2.

Next, we are having logical internal
files.

So, these are logical internal files.

So, that is our point number 3.

So, here we are having external interface
files.

So, that is our point number 4.

So, here we are having this external which
is outside of this respective process

boundary and there is a external interface
files.

And the last one is the external inquiry.

So, there is a external inquiry.

There is a point
number So, here we are having this external

programs and here
the developer is developing the software.

So, in this way, these five parameters we
have demonstrated using this diagram.

So, let us discuss each one of them into
more details.

So, at first we are going to discuss the
first parameter that is the external input.

So, every unique input
to the system from

the outside is considered as external
input.

Uniqueness of input is measured as no two
inputs should have the same formats.

So, no input, no two input should have the
same formats.

So, this is the respective external input.

These inputs can be either be a data or
some control parameters.

So, they can be categorized into three
different categories.

So, simple if the input count is low and
affects less internal files.

Complex if the input count is high and
affects more internal files.

Average in between simple and complex.

So, here we are having these three
different categories, three different

categories for the parameter external
input.

Next one we are going for external output.

All output types provided by the system
are counted in this category.

And output is considered unique if their
output format and or processing are unique.

So, if the formats are unique,
if the processing are unique, then

obviously they will be considered as the
unique output.

So, simple means if output count is low,
complex means if the output count is high

and average means in between simple and
complex.

Next one, we are having the logical
internal files.

So, every software system maintains
internal files in order to maintain its

functional information and to function
properly.

So, that is a very common property of all
the softwares.

So, these files hold the logical data of
the system.

This logical data may contain both
functional data and control data.

So, this is our logical
Simple internal files

which you
have shown in our respective diagram.

So, simple means if the number of record
types are low, complex means if the number

of record types are high and average means
in between simple and complex.

Next one we are having this one.

There is the external
interface files which

will be residing outside
of the system boundary.

So, software system may need to share its
files with some external software.

So, it may need to pass the file for
processing or as parameter to some functions.

And all these files are counted as
external interface files.

So, when this particular software will try
to interact with some other software,

some external software, then for the
communication they might be using these

external interface files.

Simple means if the number of record types
in the shared file are low.

Complex means if the number of record
types in the shared file are high.

And average means in between simple and
complex.

External inquiry.

So, that is the last parameter we are
going to discuss.

An inquiry is a combination of input and
output, where user sends some data to

unique about
and as input and the system responds

to the user with the
output of inquiry process.

So, it is a combination of input and
output.

So, where the user will send some data in
the form of inquiry and then the outputs

will be obtained from the system to the
user.

The complexity of a query is more than
external input and external output.

So, complex of the query is more than the
external input and corresponding the

external So, query is said to be unique if
its input and output are unique in terms

of formats and data.

So, here if you consider the simple
category, if query needs low processing

and its small amount of output data,
complex means if the query needs high

process and yields
large amount of output data,

average means in
between simple and complex.

So, in this way we have defined all the
three categories for all the five parameters.

So, now we are having each of these
parameters in the system is given

weightage according to their class and the
complexity.

So, here we are having this respective.

So, how many categories are there?

Three categories.

How many parameters are there?

Five parameters.

So, here we have put the respective
weightages.

The table
above, that means the previous slide

table, raw function
yields a raw function point.

So, that means in the case calculating
this, this respective weightages and the

respective this parameters, we can easily
calculate the raw function point.

So, these function points are adjusted
according to the environment complexity.

System is described
So, these are the 14

different characteristics
we have listed here.

So, these are the 14 different
characteristics.

So, these external factors are then rated
from 0 to 5.

So, 0 to 5 means how many ratings are
there?

6 ratings.

So, as mentioned below, so, no influence
means 0 and essential means 5.

So, these particular characteristics,
so, they have got they have got ranked or

rated from 0 to 5 accordingly.

So, how many such characteristics we had?

We are having we had 14 different
characteristics.

So, how many ratings?

How many different types of ratings are
possible?

So, here we are having this one is our
5 different kinds of

rating because no
influence is having the rating value 0.

So, obviously, if you multiply the
respective any value with the 0,

it will be getting 0 there.

So, all ratings are then summed up to get
this n.

So, what is the value of n?

The value of n is ranges from 0 to 70.

So, 14 types of characteristics into 5
types of rating.

So, if you go on multiplying and if you go
on adding.

So, in this case, we can have the
respective range from 0 to 70.

So, it is used to calculate the complexity
adjustment factor.

So, this is known as complexity adjustment
factor that is CAF in abbreviated form.

So, using the following formula.

So, this is the respective formula.

So, how this n will get calculated?

We are having the 14 characteristics.

We are having the 5 actually we are having
the 6 different ratings are there.

But the no influence is having the value
0.

So, when we will be going for the
multiplication.

So, that value will not be contributing
anything.

So, that is why my this value of n will be
ranging from 0 to 70 accordingly.

So, here this particular n, what is the n
here?

So, that is the CAF we are going to calculate
and n is getting calculated from here.

So, CAF is equal to what is the CAF?

That is the complexity adjustment factor
is equal to 0.65 plus 0.01 n.

So, then delivered function points
FB will be CAF into raw is equal to 0.

65 FB which we calculated
earlier depending upon those parameters.

So, this FB can then
be used to in various

metrics such as cost,
quality and productivity.

So, in this way how this function point is
working and how it can calculate the size

of a program and what are the different
parameters?

What are the different calculations are to
be done?

We have discussed that one into something
more in details.

Thanks for watching this video.