40th BCS — Written Exam: 2020 (BPSC)প্রশ্ন ও সমাধান

Software Development Life Cycle (SDLC) is a structured, phase-wise process that a software project follows from the initial idea through to retirement, ensuring predictable, quality delivery.

Main phases (in order):

1. Requirement Analysis & Planning — gather and document what the client/user needs; feasibility study, cost and schedule estimation.
2. Design — translate requirements into architecture: high-level design (system/module structure) and low-level design (data structures, algorithms, UI, database schema).
3. Implementation / Coding — developers write the source code following the design and coding standards, using version control.
4. Testing — verify the built system against the requirements (unit, integration, system, acceptance testing) to find and fix defects.
5. Deployment — release the tested software into the live/production environment for end users.
6. Maintenance — ongoing bug fixes, patches, and enhancements after release (corrective, adaptive, perfective, preventive).

flowchart TD
    A([Requirement Analysis]) --> B[Design]
    B --> C[Implementation and Coding]
    C --> D[Testing]
    D --> E[Deployment]
    E --> F[Maintenance]
    F -. feedback for next release .-> A

• Example: building a bank's mobile app — analysts gather requirements from bank staff, architects design the app/API/DB schema, developers code the modules, QA tests the login/transaction flows, the app is released on app stores, and post-release bug-fix or feature updates continue.
• Different SDLC models (Waterfall, Iterative, Spiral, Agile/Scrum) arrange these same six phases differently — Waterfall runs them strictly in sequence once, while Agile repeats them in short sprints.

Exam takeaway: memorize the 6 phases — Requirement Analysis → Design → Implementation → Testing → Deployment → Maintenance — and be ready to map any given SDLC model (Waterfall/Agile/Spiral) onto this same skeleton.