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Video Title: Halstead’s Complexity Measures
Description: Halstead’s Complexity Measures
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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Hulstead's complexity measures.

So, in this session, we are discussing the
respective method to calculate the

complexity and also we shall explain it
with a proper example.

So, in the year 1977, Mr. Maurice Howard
Hulstead introduced metrics to measure

software complexity.

Hulstead's metrics depends upon the actual
implementation of the program and it

measures which are computed directly from
the operators and the operands from the

source code in static manner.

It allows to evaluate testing time,
vocabulary, size, difficulty, errors,

efforts for this C, C++ or Java source
codes.

So, now, let us go for further detailing.

So, according to the Hulstead,
a computer program is an implementation of

an algorithm considered to be
a collection of tokens which can

be classified either in the
category of operators or operands.

Hulstead metrics think a program.

Hulstead metrics think
a program as sequence

of operators and their
associated operands.

So, here we are having one table.

So, he defines various indicators to check
complexity of a module.

So, following table states the parameters
and the respective meaning.

So, small n1 that means the number of
unique operators.

We are considering here unique operators.

Small n2, it is denoting number of unique
operands.

Capital n1, it is denoting number of total
occurrence of operators.

And capital N2 is denoting the number of
total occurrence of the operands.

So, small n1 is calculating the total
number of unique operators.

Small n2 is denoting the total number of
unique operands.

And this capital N1 and capital N2,
they are denoting the total number of What

occurrences of operators and operands
respectively?

When we select source file to view its
complexity details in metric viewer,

the following result is seen in the metric
report.

So, here we are having the respective
different meaning, the metrics are there,

meanings are there, and the mathematical
representation.

So, small n will be denoting the
vocabulary which is nothing but n1 plus n2.

That is small n1 plus small n2.

Capital n will be denoting the size,
which is nothing but n1 plus n2.

Capital n1 plus capital n2.

V stands for volume, which is length into
log of vocabulary to the base 2.

D stands for difficulty.

These are respective expressions.

We are having effort.

We are having this B.

We are having this T.

So, the respective things have got
expressed in the proper formula,

in the proper mathematical representation.

So, let us take one example for the better
understanding.

So, here we have taken one sample C code.

Now, if you judge this particular C code,
you can find that the unique operators are

main, the first packet opening and
closing, the second packet opening and

closing, int scanf ampersand
is equal to plus slash

printf, we are having this
comma and also the semicolon.

So, if you go on counting, if you go on
counting, you will be getting here total

number of unique appearance, operator will
be 12.

Now, in case of total number of unique
appearance, so if you look at this

particular program
segment, you can find that

these are the respective
appearance we are having.

So, that is small a, small
b, small c, a, b, g. This is the

one string and then 3 and
there is another string is there.

So, here if you go on counting, we
are getting this one 1, 2, 3, 4, 5, 6, 7.

So, n 2 has become 7 here.

So, what is n?

N means small n 1 plus small n 2.

What does it signify?

It signifies the vocabulary.

So, if you go on adding them, that is 12
plus 7, you are getting this 19,

which is actually denoting the vocabulary.

Next one, we are going
to calculate that how many

times these respective
operators have occurred.

So, here we are finding this one that
these are the distinct operators and if

you go on counting their occurrences,
we are getting this one as 27 and n 2 is

actually denoting the total number of
appearance in this sample code that is 15.

So, if you go on adding, we are getting
this one 42.

So, what was our capital N 1 plus capital
N 2.

So, that is our size.

So, capital N 1 plus capital N 2 was our
size and previously it was our vocabulary.

So, that is why you have written this one
as vocabulary and here is a size.

Also, it is known as program length.

So, calculated estimated program length is
having this respective expression if you

evaluate, you are getting this value that
is 62.67.

So, now how to calculate the volume?

If you come to the previous
slide, you are having this 1

there is the length into log
of vocabulary to the base 2.

So, that is the formula if you can
remember this 1 we will then seen that we

have put the respective values there that
is the log of 19 to the base 2 and 19 here

is a vocabulary you are getting to this
one.

So, now we are going to calculate the
respective difficulty.

So, here you can find these formulas are
given.

So, according to this formula,
we have put the respective values and we

have calculated it is
a difficulty, effort, time

required to program and
number of delivered bugs.

So, in this way, this is the Halstead's
complexity measures.

We have explained this one.

What are the different calculations?

What are the different mathematical
expressions?

And also, we have explained our discussion
with one example.

Thanks for watching this video.

Simply easy learning.