需求( Requirements) gineering 199ek (1)a condition or capability needed by a user to solve a problem or achieve an 2)A conditior system comp formally imp Admn用户的角度一-系统的外部行为!什么是需求？ 需求（Requirements ） [IEEE Standard Glossary of Software Engineering 1990]: (1)A condition or capability needed by a user to solve a problem or achieve an objective. (2)A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed documents. (3)A documented representation of a condition or capability as in (1) or (2) 用户的角度——系统的外部行为！