Software engineering Interview Questions And Answers

Some basic definitions of software engineering are:

The application of a disciplined engineering approach to the development of software systems.

A body of knowledge and experience in software development practice and process.

Software Engineering is all about using engineering principles for the production of software. If you like computers, like solving challenging problems and would like to make an impact on the world in which we all live, you should consider software engineering (SE).

Computer systems are an integral part of today's society. Software is a critical component of all computer systems, including the "embedded systems" used in communication networks, vehicles, consumer electronics, and medical devices. Software engineers have the knowledge and skills needed to produce high-quality, effective software on which all these computer systems depend.

BSSE program is one of the first four ABET accredited programs in the United States. Our curriculum provides a strong foundation upon which to build a successful SE career.

While computer engineering programs include courses in software, SE programs incorporate much more detail in software development practice and process, including advanced areas of software architecture, requirements management, quality assurance, and process improvement. Software engineering programs do not stress computer hardware and electronics as much as computer engineering programs do.

On the other hand, software engineering is based on computer science, as other engineering disciplines are based on natural or life sciences. However, software engineering adds an emphasis on issues of process, design, measurement, analysis and verification. In general, scientists seek new knowledge, while engineers want to build things, solve problems, and help people. Both roles are important.

Computer systems are pervasive and have a major impact on society. Software is a critical component of all computer systems, including the "embedded systems" used in communication networks, vehicles, consumer electronics and medical devices. Software engineers have the knowledge and skills needed to produce high-quality, effective software on which all these computer systems depend.

Any previous programming experience that you may have is certainly an asset, but it is not a requirement. It is a very common myth that SE is mainly programming. In fact, SE programs put a lot more emphasis on software development practice and process, including advanced areas of software architecture, requirements management, quality assurance and process improvement.

On more than one occasion, when I gave a star candidate a coding question, he zeroed in on the most optimally performant solution, identified the boundary cases, and began writing well-designed code. Midway through the problem, he makes a little error -- getting the order of operations wrong on the first try, or having an off-by-1 error, or forgetting to declare a variable.

When I point it out, the candidate responds with horror and then becomes so nervous that it impacts his performance during the rest of the interview.

The fear is unfounded. An awesome candidate making a little error is like a concert violinist playing a challenging Brahms concerto and hitting two wrong notes. Sure, the audience could tell that he made mistakes, but they don't get confused as to whether he's actually at Twinkle-Twinkle-Little-Star level.

Even if you completely bomb one question, many interviewers ask you multiple questions and will forgive a single mishap. Even bombing an entire interview is recoverable if the other interviews go well.

An architecture expresses a fundamental structural organization schema for software systems. It provides a set of predefined subsystems, specifies their responsibilities, and includes rules and guidelines for organizing the relationships between them.
* Object-Oriented/Abstract Data Style
* Layered Hierarchies
* Blackboard architecture
- involving shared access to data with loosely coupled agents
* Client/Server
* Three tier Client/Server architectures
* Peer-to-Peer Architecture

Use cases are graphical represenation of system parts and there interaction that is taking place. Normally we depict
the part of the systems who are involved in some activity as actors.
Class Diagrams are a part of designing proess. After coming up with use cases of the system, we take each use case and come up with the
classes that we need to perform that functionality. Each class will have Class Name, Attribues and Operations associate with it.
Some of the features of the classes are -
- Each class should have well defined responsibilities
- These responsibilities should be cohesive i.e. the system as a whole looks sensible and looks together.

Sequence Diagrams
They are pictorial representation of event happening according to the time line. In sequence Diagrams, we show respective class names by a small box and the event as a arrow.
Sequence Diagrams help in describing the normal course and alternative course of use cases.
VOPC - View of Participating Classes
VOPC is a a combined representation(showing) of all classes on one page.
Collaboration Diagrams
- are an alternative presentation of a sequence diagram. We uses boxes to desibe objects, the lines connecting two boxes indiate that the objects collborate with to one another and we use a multiplicity factor "*" to indiate that all elements of the aggregation receive a message.
Package Diagram
is complete set of sequence Diagrams or Collaboration Diagrams of the system.

Design Patterns are simple and elegant solutions of commonly occuring problems in software design. Design Patterns make it easier to reuse successful designs and architectures of expereinced and Professional Designers.
There are three types of Patterns -
1. Creational - Concerned with creation of objects
2. Structural - Concerned with composition of classes or objects
3. Behavioral - characterize the ways in which classes and objects interact and distribute responsibility.

Object Oriented Design Tools - Rational Rose, Rhapsody, Telelogic Tau G2
UI Design Tools - Rapid/Paper prototypes, Simple
SUMI (Software Usability Measurement Inventory ) - It will tell you how your product compares to this standardization base: whether you are about average for the market, below, or above.

What is SDLC
A software cycle deals with various parts and phases from planning to testing and deploying. All these activities are carried out in different ways, as per the needs. Each way is known as a Software Development Lifecycle Model (SDLC).
Some SDLC models
* The Linear model (Waterfall)
- Separate and distinct phases of specification and development
- All activities in linear fashion
- Next phase starts only when first one is complete
* Evolutionary development
- Specification and development are interleaved (Spiral,incremental,prototype based,Rapid Application development)
- Incremental Model (Waterfall in iteration)
- RAD(Rapid Application Development) - Focus is on developing quality product in less time
- Spiral Model - We start from smaller module and keeps on building it like a spiral. It is also called Component based development.
* Formal systems development
- A mathematical system model is formally transformed to an implementation
* Agile Methods
- Inducing flexibility into development
* Reuse-based development
- The system is assembled from existing components

RUP stands for Rational Unified Process
It deals with -
• Iterative software development process.
• Visual Modeling of Systems
• Quality Management
• Change Control Management
• Deals with the role, the activity, and the artifact
• For managing OO Software Development
Some Features of RUP are -
• Online Repository of Process Information and Description
• Templates for all major artifacts, including:
– Requirements tracking (RequisitePro templates)
– Use Cases (Word Templates )
– Project Management (Project Templates)
• Process Manuals describing key processes
PSP stands for Personal Software Process
PSP Objectives are -
– To introduce individuals to a process-based approach to developing software
– To show individuals how to measure, estimate, schedule, and track their work
– To show individuals how to improve the quality of their programs
– In general PSP improves quality and productivity
- The time saved in testing because of better quality reduces time across the project by 20-40%
Advantage of PSP -
– To manage your work & assess/build your talents/skills
– To plan better
– To track your performance precisely
– To measure the quality of your software products

What is Testing in Software Engineering
Testing is running the program(or product) under various circumstances and conditions to find errors and bugs in it. This is important as releasing a faulty product will not only cause serious problems to the end user, it will also harm the companies reputation. There are various kind of Testing conditions and which one to use depends on type of product.
Types of Testing in Software Engineering
As per Test Target, there is * Unit Testing * Integration Testing * System Testing As per Test Objective, there is * User Acceptance Testing * Installation Testing * Functional * Alpha / Beta testing * Regression * Performance * Stress * Usability * Configuration * Smoke (Sanity Test) Let's see them one by one -

SRS stands for Software Requirement Specification.
It establishes the basis for agreement between customers and contractors or suppliers on what the software product is expected to do, as well as what it is not expected to do.
Some of the features of SRS are -
• It sets permits a rigorous assessment of requirements before design can begin.
• It sets the basis for software design, test, deployment, training etc. It also sets pre-requisite for a good design though it is not enough.
• It sets basis for software enhancement and maintenance.
• It sets Basis for Project plans like Scheduling and Estimation.

Functional Requirements are the Expected functionality or services from the system.
Non - Functional Requirements are System property and constraints. Now Constraints can be on requirements itself. Some examples are of Response time, 24X7 availability of the system etc.

Software Requirements are Descriptions and specifications of a system–A requirementis a condition or capability to which the system must conform and Define. A system is designed with certain functionality in mind and to ome up with that functionality and its specification right at the beginning is Requirement Engineering. Requirements Engineering–Eliciting, organizing, and documenting the requirements of the system–The process of establishing the services that the customer requires from a system and the constraints under which it operates and is developed Software requirements should be •Clear
•complete
•Unambiguous
•Quantitative

The steps involved are
Planning
Analysis
Design
coding
testing.
After testing maintenance of the product in also involved.

System testing conducted once again according to hardware configuration requirements. Installation procedures may also be verified.

The Tools used in Unit Testing are debuggers, tracers and is Done by Programmers. Unit testing verifies the functioning in isolation of software pieces which are separately testable.

We impose abnormal input to stress the capabilities of the software. Input data volume, input data rate, processing time, utilization of memory, etc. are tested beyond the designed capacity.

It checks that the functional specifications are correctly implemented. Can also check if Non Funcctional behavior is as per expectations.

Testing conducted to determine whether or not a system satisfies its acceptance criteria and to enable the customer to determine whether or not to accept the system. It is Done against requirements and is done by actual users.

It is verifying that the software meets the specified performance requirements (response time, volume.

It is Used when software meant for different types of users. It also check that whether the software performs for all users.