Introduction of Software Engineering

Chapter - 1
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• What is the Software Engineering ?
Software engineering is a field of Computer science, for designing and
writing programs for computers or other electronic devices. A software
engineer writes software (or changes existing software) using methods that make it
better quality.
• Another view
In other words, software engineering is a discipline whose aim is the
production of fault-free software, delivered on time and within budget, that satisfy
the client’s needs. Furthermore, the software must be easy to modify when the
user’s needs change.
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• What are Code of Ethics ?
The appropriate set(s) of standards for professional practice of Software
Engineering upon which industrial decisions, professional certification, and
educational curricula (syllabuses) can be based and share their systems.
•• Why is needed ?
 Standardization
 Easy to understandable
 Easy to intergrade
 Easy for administration
 Expandable
 To maintain System Development Life Cycle - SDLC

• Who's define Code of Ethics ?
 IEEE Board of Governors established steering committee (May, 1993)
 ACM Council endorsed Commission on Software Engineering (Late 1993)
 Joint steering committee established by both societies (January, 1994)
• Goal of Ethics
 Adopt standard definitions
 Define required body of knowledge and recommended practices
 Define ethical standards
 Define educational curricula for undergraduate, graduate(MS) and continuing
education (for retraining and migration)

Code of Ethics
1. Product
2. Public
3. Judgment
4. Client and Employer
5. Management
6. Profession
7. Colleagues
8. Self

1. Product
1.01 Ensure adequate software specification
1.02 Understand specifications fully
1.03 Ensure you are suitably qualified
1.04 Ensure all goals are achievable
1.05 Ensure proper methodology use
1.06 Ensure good project management
1.07 Ensure all estimates are realistic
1.08 Ensure adequate documentation
1.09 Ensure adequate testing and debugging
1.10 Promote privacy of individuals
1.11 Use data legitimately
1.12 Delete outdated and flawed data
1.13 Identify and address contentious issues
1.14 Promote maximum quality and minimum cost
1.15 Follow appropriate industry standards

2. Public
2.01 Disclose any software-related dangers
2.02 Approve only safe, well tested software
2.03 Only sign documents in area of competence
2.04 Cooperate on matters of public concern
2.05 Produce software that respects diversity
2.06 Be fair and truthful in all matters
2.07 Always put the public’s interests first
2.08 Donate professional skills to good causes
2.10 Accept responsibility for your own work

3. Judgment
3.01 Maintain professional objectivity
3.02 Only sign documents within your responsibility
3.03 Reject bribery
3.04 Do not accept secret payments from the client
3.05 Accept payment from only one source for a job
3.06 Disclose conflicts of interest
3.07 Avoid conflicting financial interests
3.08 Temper technology judgments with ethics

4. Client and Employer
4.01 Provide services only where competent
4.02 Ensure resources are authentically approved
4.03 Only use property as authorized by the owner
4.04 Do not use illegally obtained software
4.05 Honor confidentiality of information
4.06 Raise matters of social concern
4.07 Inform when a project becomes problematic
4.08 Accept no detrimental outside work
4.09 Represent no interests adverse to your employer

5. Management
5.01 Assure standards are known by employees
5.02 Assure knowledge of confidentiality protocols
5.03 Assign work according to competence
5.04 Provide due process for code violations
5.05 Develop fair ownership agreements
5.06 Accurately describe conditions of employment
5.07 Offer only fair and just remuneration
5.08 Do not prevent a subordinate’s promotion
5.09 Do not ask a person to breach this code

6. Profession
6.01 Associate with reputable people
6.02 Promote commitment of this code
6.03 Support followers of this code
6.04 Help develop an ethical environment
6.05 Report suspected violations of this code
6.06 Take responsibility for errors
6.07 Only accept appropriate remuneration
6.08 Be accurate and honest regarding software
6.09 Place professional interests before personal
6.10 Obey all laws governing your work
6.11 Exercise professional responsibility
6.12 Promote public knowledge of the subject
6.13 Share software knowledge with the profession

7. Colleagues
7.01 Assist colleagues in professional development
7.02 Review other’s work only with their consent
7.03 Credit fully the work of others
7.04 Review others work candidly
7.05 Give fair hearing to colleagues
7.06 Assist colleagues’ awareness of work practices
7.08 Do not hinder a colleague’s career
7.09 Do not pursue a job offered to a colleague
7.10 Seek help with work outside your competence

8. Self
8.01 Further your own professional knowledge
8.02 Improve your ability to produce quality work
8.03 Improve your ability to document work
8.04 Improve your understanding of work details
8.05 Improve your knowledge of relevant legislation
8.06 Improve your knowledge of this code
8.07 Do not force anyone to violate this code
8.08 Consider code violations inconsistent with
software engineering

• Non Structure Programming
1. Non structure programming is also called Exploratory Programming.
2. A program in a non-structured language usually consists of sequentially ordered
commands, or statements, usually one in each line.
3. The lines are usually numbered or may have labels: this allows the flow of
execution to jump to any line in the program.
4. Non-structured programming introduces basic control flow concepts such as
loops, branches and jumps.
5. Although there is no concept of procedures in the non-structured paradigm,
subroutines are allowed.
6. Unlike a procedure, a subroutine may have several entry and exit points, and a
direct jump into or out of subroutine is (theoretically) allowed. This flexibility
allows realization of coroutines (multiple entry points).

7. There is no concept of local variables in non-structured programming (although
for assembly programs), but labels and variables can have a limited area of
effect (For example, a group of lines).
8. This means there is no (automatic) context refresh when calling a subroutine, so
all variables might retain their values from the previous call.
9. Where no subroutine state values are needed after the recursive call--are
possible if variables dedicated to the recursive subroutine are explicitly cleared
(or re-initialized to their original value) on entry to the subroutine. The depth of
nesting also may be limited to one or two levels.
10.Non-structured languages allow only basic data types, such as numbers, strings
and arrays (numbered sets of variables of the same type).
11.First GOTO statement is also part of non structure programming where program
may jump very frequently.
12.Like early stage assembly language (in 1950’s)

• Structure Programming
1. Structure programming is also called Procedural Programming.
2. This approach provide aimed at improving the clarity, quality, and development
time of a computer program by making extensive use of subroutines , block
structures and for and while loops
3. It’s against to using simple tests and jumps such as the GOTO statement which
is difficult both to follow and to maintain.
4. Procedures also known as routines, subroutines, methods, or functions (control
programs), simply contain a series of computational steps to be carried out.
5. Any given procedure might be called at any point during a program's execution,
including by other procedures or itself.
6. Procedural programming is a list or set of instructions telling a computer what to
do step by step and how to perform from the first code to the second code.
7. Procedural programming languages include C, ALGOL, Fortran, Pascal,
and BASIC.

8. Structured programming techniques have been developed to ensure correct
processing of control breaks in languages such as COBOL and to ensure
that conditions such as empty input files and sequence errors are handled
properly.
9. Control Structure:
a. "Sequence"; ordered statements or subroutines executed in sequence.
b. "Selection"; one or a number of statements is executed depending on the
state of the program. This is usually expressed with keywords such
as if..then..else..end if.
c. "Iteration"; a statement or block is executed until the program reaches a
certain state, or operations have been applied to every element
of a collection. This is usually expressed with keywords such
as while, repeat, for or do..until.
10. Often it is recommended that each loop should only have one entry point (and
in the original structural programming, also only one exit point, and a few
languages enforce this).

11. Subroutines : Callable units such as procedures, functions, methods, or
subprograms are used to allow a sequence to be referred to by a single
statement.
12. Blocks: Blocks are used to enable groups of statements to be treated as if they
were one statement. Block-structured languages have a syntax for enclosing
structures in some formal way, such as an if-statement bracketed by if..fi as
in ALGOL 68
13. Early exit : The most common deviation from structured programming is early
exit from a function or loop. At the level of functions, this is a return statement.
At the level of loops, this is a break statement (terminate the loop)
or continue statement (terminate the current iteration, proceed with next
iteration).
14. Multiple entry : More rarely, subprograms allow multiple entry. It is very rare for
subprograms to allow entry to an arbitrary position in the subprogram, as in this
case the program state (such as variable values) is uninitialized or ambiguous,
and this is very similar to a GOTO.

Introduction of Software Engineering

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