THEORY EXAMINATION (SEM–IV) 2016-17 SOFTWARE ENGINEERING

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Course: B.Tech (IT / CSE)
Subject Code: EIT402
Subject Title: Software Engineering
Exam Type: Theory
Duration: 3 Hours
Maximum Marks: 100

SECTION – A (10 × 2 = 20 Marks)

Short questions assessing definitions and conceptual clarity

No.	Question	Explanation
(a)	Program vs Software	Program → a set of instructions performing a specific task. Software → a complete, well-documented product consisting of programs, procedures, and documentation for a particular function.
(b)	Advantages of Waterfall Model	Simple, structured, easy to manage, well-defined stages, and suitable for smaller or stable requirement projects.
(c)	Feasibility Study	Evaluates technical, economic, operational, and schedule viability before project initiation.
(d)	ER Diagram	Entity-Relationship diagram visually represents database entities, attributes, and relationships.
(e)	Properties of Modular System	Independence, reusability, cohesion, low coupling, and maintainability.
(f)	Data Design at Architectural Level	Defines data structures, storage organization, and database schema that support software architecture.
(g)	Structural Testing	Also known as white-box testing, checks internal logic and code structure (conditions, loops, paths).
(h)	Software Reverse Engineering	Analyzing existing software to recover design or requirement specifications for maintenance or enhancement.
(i)	Encapsulation	Bundling of data and functions that operate on that data into a single unit (class); hides implementation details.
(j)	Functional Requirements	Define what the system should do — e.g., input/output, computations, data manipulation, and user interactions.

SECTION – B (5 × 10 = 50 Marks)

Descriptive and applied questions focusing on SDLC, design, testing, and measurement

(a) Prototype Model

Concept: Builds a working model early in development for user feedback.

Advantages: Early error detection, better user satisfaction.

Effect on Cost: Increases early development cost but reduces rework and maintenance, lowering total lifecycle cost.

(b) Software Maintenance

Definition: Modification of software after delivery to correct faults, improve performance, or adapt to environment changes.

Types:

Corrective: Fixing defects.

Adaptive: Updating for new platforms or regulations.

Perfective: Enhancing performance or UI.

Preventive: Improving maintainability and reliability.

(c) Software Testing Levels

Unit Testing: Tests individual modules.

Integration Testing: Tests interaction among modules.

System Testing: Validates complete integrated system.

Acceptance Testing: Confirms software meets user needs.

(d) Software Risk & Risk Management

Software Risk: Potential problems affecting project success (technical, financial, operational).

Activities:

Risk Identification

Risk Analysis

Risk Prioritization

Risk Mitigation & Monitoring

(e) Cohesion and Coupling

Concept	Definition	Example
Cohesion	Degree to which elements inside a module belong together.	Functional, Sequential, Communicational Cohesion.
Coupling	Degree of interdependence between modules.	Data, Control, Stamp, Content Coupling.
Goal: High cohesion + Low coupling → better maintainability.

(f) Verification vs Validation

Verification	Validation
“Are we building the product right?”	“Are we building the right product?”
Ensures process adherence.	Ensures final output meets user needs.
Reviews, walkthroughs.	Testing and acceptance.

(g) Cyclomatic Complexity

Formula: V(G)=E−N+2PV(G) = E - N + 2PV(G)=E−N+2P
where E = edges, N = nodes, P = connected components.

Indicates independent paths in code; higher complexity = more testing effort.

(h) Good Software Design

Criteria: Modularity, flexibility, maintainability, efficiency, usability, portability.

Goal: Enhance software quality attributes — correctness, reliability, performance, and scalability.

SECTION – C (2 × 15 = 30 Marks)

Long-form analytical and applied questions

Q3. (a) Level-1 DFD of Library Management System

Processes:

Book Issue/Return

Member Registration

Catalog Management

Fine Calculation
Data Stores: Book Database, Member Database.
External Entities: Librarian, Student.

(b) Halstead Metrics (Code Measurement)

Given: C program for GCD.
Formulas:

n1=Distinct operators,n2=Distinct operandsn_1 = \text{Distinct operators}, \quad n_2 = \text{Distinct operands}n1=Distinct operators,n2=Distinct operands N1=Total operators,N2=Total operandsN_1 = \text{Total operators}, \quad N_2 = \text{Total operands}N1=Total operators,N2=Total operands Length (N)=N1+N2\text{Length (N)} = N_1 + N_2Length (N)=N1+N2 Volume (V)=N×log⁡2(n1+n2)\text{Volume (V)} = N \times \log_2(n_1 + n_2)Volume (V)=N×log2(n1+n2)

Used for quantitative measurement of software complexity and effort.

Q4. COCOMO Estimation

COCOMO (Constructive Cost Model):

Effort (PM)=a(KLOC)b\text{Effort (PM)} = a (KLOC)^bEffort (PM)=a(KLOC)b Development Time (TDEV)=c(Effort)d\text{Development Time (TDEV)} = c (Effort)^dDevelopment Time (TDEV)=c(Effort)d Cost=Effort×Cost/PM\text{Cost} = Effort \times Cost/PMCost=Effort×Cost/PM

Phases Estimated: Size → Effort → Duration → Cost.
Mode Examples: Organic, Semi-Detached, Embedded.

Q5. (a) Software Requirement Specification (SRS)

Definition: A formal document that defines system’s functional and non-functional requirements.
Template:

Introduction Overall Description

Functional Requirements Non-functional Requirements

System Interfaces Performance & Constraints

(b) Spiral Model

Phases:

Objective Setting Risk Analysis

Development & Validation Planning for Next Iteration

Advantages: Risk control, iterative refinement, user feedback.
Disadvantages: Expensive, complex, not suitable for small projects.

Summary

This Software Engineering (EIT402) paper tests:

Unit	Focus Area	Key Topics
I	SDLC Models	Waterfall, Prototype, Spiral, Incremental
II	Software Design	Modularity, Cohesion, Coupling, DFD
III	Measurement & Metrics	Halstead, Cyclomatic Complexity, COCOMO
IV	Testing & Validation	Unit, Integration, System, Acceptance
V	Maintenance & Quality	SRS, Reverse Engineering, Risk Management