Briones-Ruales(Source Code Maintenance Tools)

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Source Code MetricsSource Code

program instructions written as an ASCII textfile; must be translated by a compiler or

interpreter or assembler into the object codefor a particular computer before execution.

Metric

is the measurement of a particularcharacteristic of a program's performance orefficiency.


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Source Lines of Code (SLOC)

are asoftware metricused to measure thesize of a software program by counting thenumber of lines in the text of the program's

source code.

SLOC is typically used to predict the amount ofeffort that will be required to develop a

program, as well as to estimateprogramming productivityor effort once thesoftware is produced.
http://en.wikipedia.org/wiki/Software_metrichttp://en.wikipedia.org/wiki/Source_codehttp://en.wikipedia.org/wiki/Programming_productivityhttp://en.wikipedia.org/wiki/Programming_productivityhttp://en.wikipedia.org/wiki/Source_codehttp://en.wikipedia.org/wiki/Software_metric


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Software Metricsare a special kind of analysis focused on the structure of the

source code.

Classic software metrics range in variety from the very simpleSource Lines of Code (SLOC) to more complex measures suchas Cyclomatic Complexity measurements.

The goal is obtaining objective, reproducible and quantifiablemeasurements, which may have numerous valuable applications inschedule and budget planning, cost estimation, quality assurancetesting, software debugging, software performance optimization, andoptimal personnel task assignments.
http://localhost/var/www/apps/conversion/current/tmp/scratch_6/reportmonzons.ppthttp://localhost/var/www/apps/conversion/current/tmp/scratch_6/reportmonzons.ppthttp://localhost/var/www/apps/conversion/current/tmp/scratch_6/reportmonzons.ppthttp://localhost/var/www/apps/conversion/current/tmp/scratch_6/reportmonzons.ppthttp://localhost/var/www/apps/conversion/current/tmp/scratch_6/reportmonzons.ppt


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Programming Productivity

refers to a variety of software development issues andmethodologies affecting the quantity and quality of codeproduced by an individual or team.

Amount of code that can be created or maintained perprogrammer (often measured in source lines of code per day)

Detecting and avoiding errors

Software cost estimation (cost being a direct consequence ofproductivity)
http://en.wikipedia.org/wiki/Source_lines_of_codehttp://en.wikipedia.org/wiki/Source_lines_of_code


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Cyclomatic complexity

Cyclomatic complexity (orconditional complexity)

is a software metric (measurement). It wasdeveloped by Thomas J. McCabe, Sr. in 1976 and isused to indicate the complexity of a program. It

directly measures the number of linearlyindependent paths through a program'ssource code.

Cyclomatic complexity may also be applied toindividual functions, modules, methods orclasseswithin a program.
http://en.wikipedia.org/wiki/Software_metrichttp://en.wikipedia.org/wiki/Source_codehttp://en.wikipedia.org/wiki/Function_%28computer_science%29http://en.wikipedia.org/wiki/Modular_programminghttp://en.wikipedia.org/wiki/Method_%28computer_science%29http://en.wikipedia.org/wiki/Class_%28computer_science%29http://en.wikipedia.org/wiki/Class_%28computer_science%29http://en.wikipedia.org/wiki/Method_%28computer_science%29http://en.wikipedia.org/wiki/Modular_programminghttp://en.wikipedia.org/wiki/Function_%28computer_science%29http://en.wikipedia.org/wiki/Source_codehttp://en.wikipedia.org/wiki/Software_metric


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Two Major Types of SLOC

Measures

Physical SLOC (LOC)

is a count of lines in the text of theprogram's source code includingcomment lines. Blank lines are alsoincluded unless the lines of code in asection consist of more than 25% blanklines. In this case blank lines in excessof 25% are not counted toward lines ofcode.


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Logical SLOC (LLOC)

measure the number of"statements", but their specific

definitions are tied to specific

computer languages (one simple

logical SLOC measure forC-like

programming languages is the

number of statement-terminating

semicolons).
http://en.wikipedia.org/wiki/C_(programming_language)http://en.wikipedia.org/wiki/Programming_languagehttp://en.wikipedia.org/wiki/Programming_languagehttp://en.wikipedia.org/wiki/C_(programming_language)


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Example

for (i = 0; i < 100; i += 1) printf("hello"); /* How many lines of code is this? */

In this example we have:

1 Physical Lines of Code (LOC)

2 Logical Line of Code (LLOC) (forstatement and printfstatement)

1 comment line
http://en.wikipedia.org/wiki/For_loophttp://en.wikipedia.org/wiki/Printfhttp://en.wikipedia.org/wiki/Printfhttp://en.wikipedia.org/wiki/For_loop


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/* Now how many lines of code is this? */for (i = 0; i < 100; i += 1)

{

printf("hello");}

In this example we have:5 Physical Lines of Code (LOC):

2 Logical Line of Code (LLOC):

1 comment line:


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SLOC

is particularly ineffective atcomparing programs written indifferent languages unless

adjustment factors are applied tonormalize languages.


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C COBOL

#include 000100 IDENTIFICATION DIVISIONS.

main(void) 000200 PROGRAM-ID HELLOWORLD.

{ 000300

printf("\nHello\n");} 000400*

000500 ENVIRONMENT DIVISION.

000600 CONFIGURATION SECTION.

000700 SOURCE-COMPUTER. RM-COBOL.

000800 OBJECT-COMPUTER. RM-COBOL.

000900

001000 DATA DIVISION.

001100 FILE SECTION.

001200

100000 PROCEDURE DIVISION.

100100

100200 MAIN-LOGIC SECTION.

100300 BEGIN.

100400 DISPLAY " " LINE 1 POSITION 1 ERASE EOS.100500 DISPLAY "Hello world!" LINE 15 POSITION 10.

100600 STOP RUN.

100700 MAIN-LOGIC-EXITS.

100800 EXIT.

Lines of code: 4(excluding whitespace) Lines of code: 17 (excluding whitespace)


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Maintenance Tools and

Techniques

Software maintenance tools are programs used bysoftware engineers to increase their productivity forgathering data, detecting bugs and managingtheir software. Without these tools, it would be

nearly impossible for these engineers to go throughthousands of lines of code to find errors ordetermine why a particular server went down.

Software maintenance involves a number ofspecific techniques. One technique is static slicing,which is used to identify all the program code thatcan modify some variable


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Needs of Maintenance

Maintenance is needed to ensure that the software continuesto satisfy user requirements. Maintenance must be performedin order to:

Correct faults Improve the design

Implement enhancements

Interface with other systems

Adapt programs so that different hardware, software, system

features, and telecommunications facilities can be used

Migrate legacy software

Retire software


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The functionality of software maintenance

tools include the following:

1. Program understanding:

This function can provide two types of programknowledge syntactical knowledge, and semanticknowledge.

*sub-divided into two types: analysis-oriented tools, and code-oriented tools.

2. Ripple effect analysis:

aims to trace the extent of these secondaryeffects. This function should not only trace the side effect inthe program due to code modification, it also be able toanalyzeripple effects at a higher abstraction level.


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3. Software Retesting:

This functions are not very different from the originalsoftware testing during the initial software developmentphase. Should incorporate knowledge gained in previoustesting as well as information provided by the ripple effectanalysis.

4. Knowledge redocumenting:

A clear and precise documentation of the modifiedsystem is crucial to software maintainability. This function helpsto update existing documents to ensure that all changes tothe software are properly reflected in this documentation.


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5. Information repository:

Two types of information are important: history databasewhich provides a recorded history of the system modifications.,and semantic database which preserves the integrity andcurrency of the system characteristics.

6. Display function:

This provides the capabilities to display in textual andgraphical format of the program information as a result of the

maintenance modification.


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The user will also be able to navigate or browse theexisting program structure using maintenance tools. The tool

must have the capability to represent and examine data andprogram structure from different viewpoints.

7.Tool interconnections:

Considered important during tool evaluations. Tool

interconnections affect how toll works in an organization


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Maintenance consists of four

parts:1. Corrective maintenance:

Reactive modification of a software product performedafter delivery to correct discovered problems. It deals with

fixing bugs in the code. Deals of repair of faults and defectsfound.

2. Adaptive maintenance:

Modification of a software product performed after

delivery to keep a software product usable in a changed orchanging environment. It deals with adapting the software tonew environments


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3. Perfective maintenance:

Modification of a software product after delivery toimprove performance or maintainability. It deals with updatingthe software according to changes in user requirements.

4. Preventive maintenance:

Modification of a software product after delivery todetect and correct latent faults in the software product beforethey become effective faults. It deals with updating

documentation and making the software more maintainable.


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