Requirement engineering or software requirements is the starting point of software development process in which all reuqirements are gather and documented, requirement engineering describes basic architecture features and function of software system which is going to develop, good understanding of requirement leads to good software which is acceptable by end user and according to its need and also help in good software naintenance.









requirement engineering is important role in development, maintenance and cost,if reuirements are identified correctly and documented it leads to strong foundation but if requirements are understand incorrectly then functionality deilver is not accept by user or if any requirement is missing or forgot and find in the middle of development then correcting it or implement it leads to high cost and leads late delivery of software system.

Requyrement engineering definition

By Ian Summerville

“requirements are a specification of what should be

implemented. They are descriptions of how the system should behave, or of a system

property or attribute. They may be a constraint on the development process of the system.”

By Alan Davis

“software requirements as a user need or necessary feature, function,

or attribute of a system that can be sensed from a position external to that system.”

Requirement engineering has four levels

Business reuirement

User Requirement

Functional requirement

Non functional requirement

Business reuirement

Business reuirement are those requirement what is achieved by software which is going to be develop like what economics, and managerial need are met and utomation of any department ,managing and maintaining records etc.

Business reuirement describes cost .budgets,expenditure,time schedule and all resoruces involve in the development of software. Business reuirement is broad and all other requirements of software are derived from Business reuirement.

User Requirement

User requirements are those reuirement which are delivered by the software system to end user or to an corporation or orgranization,User Requirement are the features and function which is provided by software to solve problem and achieve its work and objectives easily.

Functional requirement

Functional requirement are those requirements that describes what functions are implemented on the basis of user reqouirements and feature perform by the software.It also describes how how functions are actually implemented in the

software form technical point of view like coding tool,technique,hardwareetc,it also elaborate function want to implement in software.

Non functional reuirement

Non functional reuirement are those requirement which describes factors tha indirectly effect in software, for ex we want to develop an ssytem that operate in web environment, so this is Non functional reuirement, it also describe logucal and architecture of software, it also describe other factor like on which operating system itexectue whether it is android,window,linux etc.

Stakeholders

Stakeholders are all those persons and parties that related to software and software development either directly or indirectly whether they are software developers,software tester,project planner,end users,vendors,marketing teams,maintenabce team,enterprenurs,legal advisors etc.