Sahithyan's S2 — Program Construction
Introduction to Program Construction
Program construction is a methodological process that starts from a user’s requirements and end with a working program.
The methodology
System level
- System requirements analysis
- System requirements specification
- System architecture design
- System validation (checking if the specification captures the customer’s requirements)
Software level
- Software requirements analysis
- Software requirements specification
- Software architecture design
- Software component/module design
- Program coding and testing
- Software deployment and maintenance
- Software verification (checking if the software meets the specifications)
Requirements
Functional requirements
A statement of a piece of required functionality or a behavior that a system will exhibit under specific conditions.
The above definition is from Grady Booch, James Rumbaugh, and Ivar Jacobson and is a generally accepted one.
Non-functional requirements
A requirement that specifies criteria that can be used to judge the operation of a system. Conveniently identified as illities. These are subjetive, ambigous and conflicting.
Examples:
- Usability
- Reliability
- Safety
- Responsiveness
Summary
| Functional req. | Non-functional req. | |
|---|---|---|
| Objective | Describe what product does | Describe how product works |
| End result | Define product features | Define product properties |
| Focus | On user requirements | On user expectations |
| Documentation | Captured in use cases | Captured as a quality attribute |
| Origin type | Defined by user | Defined by developers |