Loc and function point

Software ProjectPlanning
2
After the finalization of SRS, we would
estimate size, cost and development time
like to
of the
project. Also, in many cases, customer may like to
know the cost and development time even prior to
finalization of the SRS.

Software Project
Planning
3
In order to conduct a successful software project, we
must understand:
▪ Scope of work to be done
▪ The risk to be incurred
▪ The resources required
▪ The task to be accomplished
▪ The cost to be expended
▪ The schedule to be followed

Software planning begins before technical work starts, continues as
the software evolves from concept to reality, and culminates only
when the software is retired.
Software Project
Planning
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Size estimation
Cost estimation Development time
Resources
requirements
Project
scheduling
Fig. 1: Activities during Software
Project Planning

1. int. sort (int x[ ], int n)
2. {
3. int i, j, save, im1;
4. /*This function sorts array x in ascending order */
5. If (n<2) return 1;
6. for (i=2; i<=n; i++)
7. {
8. im1=i-1;
9. for (j=1; j<=im; j++)
10. if (x[i] < x[j])
11. {
12. Save = x[i];
13. x[i] = x[j];
14. x[j] = save;
15. }
16. }
17. return 0;
18. }
• Size Estimation
• Lines of Code (LOC)
• If LOC is simply a count of the
number of lines then figure shown
below contains 18 LOC .
• When comments and blank
lines are ignored, the program in
figure 2 shown below contains 17
LOC. 5
Fig. 2: Function for sorting an array

0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
Jan 1993 Jun 1994 Oct 1995 Mar 1997 Jul 1998 Dec 1999 Apr 2001
TotalLOC
Total LOC ("wc -l") -- development releases
Total LOC ("wc -l") -- stable releases
Total LOC uncommented -- development releases
Total LOC uncommented -- stable releases
Growth of Lines of Code (LOC)
Software Project
Planning
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Furthermore, if the main interest is the size of the program
for specific functionality, it may be reasonable to include
executable statements. The only executable statements in
figure shown above are in lines 5-17 leading to a count of
13. The differences in the counts are 18 to 17 to 13. One
can easily see the potential for major discrepancies for
large programs with many comments or programs written
in language that allow a large number of descriptive but
non-executable statement. Conte has defined lines of code
as:
SoftwareProjectPlanning
7

“A line of code is any line of program text that is not a
comment or blank line, regardless of the number of
statements or fragments of statements on the line. This
specifically includes all lines containing program header,
declaration, and executable and non-executable
statements”.
This is the predominant definition for lines of code used
by researchers. By this definition, figure shown above
has 17 LOC.
SoftwareProjectPlanning

The principle of Albrecht’s function point analysis (FPA) is that a system is
decomposed into functional units.
▪ Inputs
▪ Outputs
▪ Enquiries
:
:
:
▪ Internal logical
files
:
▪ External interface
files
:
information entering the
system information leaving
the system
requests for instant access
to information
information held within
the system
information held by other
system that is used by the
system being analyzed.
Software Project
Planning
1
0

ILF
EIF
User
applications
System
Outputs
Inputs
The FPA functional units are shown in figure given below:
User
Inquiries
Other
ILF: Internal logical files
EIF: External interfaces
Fig. 3: FPAs functional units System
Software Project
Planning
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1

Software Project
Planning
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2
The five functional units are divided in two categories:
(i) Data function types
▪ Internal Logical Files (ILF): A user identifiable group of
logical related data or control information maintained
within the system.
▪ External Interface files (EIF): A user identifiable group of
logically related data or control information referenced by
the system, but maintained within another system. This
means that EIF counted for one system, may be an ILF in
another system.

Software Project
Planning
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4
Special features
➢ Function point approach is independent of the language,
tools, or methodologies used for implementation; i.e. they
do not take into consideration programming languages,
data base management systems, processing hardware or
any other data base technology.
➢ Function points can be estimated from requirement
specification or design specification, thus making it
possible to estimate development efforts in early phases of
development.

Software Project
Planning
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➢ Function points are directly linked to the statement of
requirements; any change of requirements can easily
be followed by a re-estimate.
➢ Function points are based on the system user’s
external view of the system, non-technical users of
the software system have a better understanding of
what function points are measuring.

Counting function points
Functional Units
Weighting factors
Low Average High
External Inputs (EI) 3 4 6
External Output (EO) 4 5 7
External Inquiries (EQ) 3 4 6
External logical files (ILF) 7 10 15
External Interface files (EIF) 5 7 10
Table 1 : Functional units with weighting factors
Software Project
Planning

The weighting factors are identified for all
functional units and multiplied with the functional
units accordingly. The procedure for the
calculation of Unadjusted Function Point (UFP) is
given in table shown above.
Software Project
Planning
1
8

The procedure for the calculation of UFP in mathematical
form is given below:
5 3
UFP  ∑∑Zij wij
i1 J 1
Where i indicate the row and j indicates the column of Table 1
Wij : It is the entry of the ith row and jth column of the table 1
Zij : It is the count of the number of functional units of Type i that
have been classified as having the complexity corresponding to
column j.
Software Project
Planning
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Organizations that use function point methods develop a criterion for
determining whether a particular entry is Low, Average or High.
Nonetheless, the determination of complexity is somewhat
subjective.
FP = UFP * CAF
Where CAF is complexity adjustment factor and is equal to [0.65 +
0.01 x ΣFi]. The Fi (i=1 to 14) are the degree of influence and are
based on responses to questions noted in table 3.
Software Project
Planning
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54
Table 3 : Computing function points.
Rate each factor on a scale of 0 to 5.
0 1 2 3
No
Influence
Average EssentialIncidental Moderate Significant
Number of factors considered ( Fi )
1. Does the system require reliable backup and recovery ?
2. Is data communication required ?
3. Are there distributed processing functions ?
4. Is performance critical ?
5. Will the system run in an existing heavily utilized operational environment ?
6. Does the system require on line data entry ?
7. Does the on line data entry require the input transaction to be built over multiple screens
or operations ?
8. Are the master files updated on line ?
9. Is the inputs, outputs, files, or inquiries complex ?
10.Is the internal processing complex ?
11.Is the code designed to be reusable ?
12.Are conversion and installation included in the design ?
13.Is the system designed for multiple installations in different organizations ?
14.Is the application designed to facilitate change and ease of use by the user ?
Software Project
Planning
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1

Functions points may compute the following important metrics:
Productivity
Quality
=
=
FP / persons-months
Defects / FP
Cost = Rupees / FP
Documentation = Pages of documentation per
FP
These metrics are controversial and are not universally acceptable.
There are standards issued by the International Functions Point User
Group (IFPUG, covering the Albrecht method) and the United
Kingdom Function Point User Group (UFPGU, covering the MK11
method). An ISO standard for function point method is also being
developed.
Software Project
Planning
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2

Example: 4.1
Consider a project with the following functional units:
Number of user inputs
Number of user outputs
Number of user enquiries
Number of user files
Number of external interfaces
= 50
= 40
= 35
= 06
= 04
Assume all complexity adjustment factors and weighting factors are
average. Compute the function points for the project.
Software Project
Planning
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Software Project
Planning
Solution
We know 5 3
i1 J 1
UFP = 50 x 4 + 40 x 5 + 35 x 4 + 6 x 10 + 4 x 7
= 200 + 200 + 140 + 60 + 28 = 628
CAF = (0.65 + 0.01 ΣFi)
= (0.65 + 0.01 (14 x 3)) = 0.65 + 0.42 = 1.07
FP = UFP x CAF
= 628 x 1.07 = 672

Software Project
Planning
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Example:4.2
An application has the following:
10 low external inputs, 12 high external outputs, 20 low
internal logical files, 15 high external interface files, 12
average external inquiries, and a value of complexity
adjustment factor of 1.10.
What are the unadjusted and adjusted function point counts ?

FP = UFP x CAF
= 452 x 1.10 = 497.2.
Solution
Unadjusted function point counts may be calculated using
as:
5 3
i1 J 1
= 10 x 3 + 12 x 7 + 20 x 7 + 15 + 10 + 12 x 4
= 30 + 84 +140 + 150 + 48
= 452
Software Project
Planning
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Example: 4.3
Consider a project with the following parameters.
(i) External Inputs:
(a) 10 with low complexity
(b)15 with average complexity
(c) 17 with highcomplexity
(ii) External Outputs:
(b)13 with high complexity
(iii) External Inquiries:
(b) 4 with average complexity
(c) 2 high complexity
Software Project
Planning
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Software Project
Planning
(iv) Internal logical files:
• (a) 2 with averagecomplexity (b)1 with high
complexity
(v) External Interface files:
• (a) 9 with lowcomplexity
• In addition to above, system requires
i. Significant data communication
ii. Performance is very critical
iii.Designed code may be moderately reusable
iv. System is not designed for multiple installation in different organizations.
• Other complexity adjustment factors are treated as average. Compute the function
points for the project.
2
8

14
∑Fi
3+4+3+5+3+3+3+3+3+3+2+3+0+3=41
i1
CAF = (0.65 + 0.01 x ΣFi)
= (0.65 + 0.01 x 41)
= 1.06
FP = UFP x CAF
= 424 x 1.06
= 449.44
Hence FP = 449
Software Project
Planning
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0

Relative Cost of Software Phases
Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age
International Publishers, 2007 31

Loc and function point

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