ISBN : 978-81-963532-2-3 (E-Book) should define the details of the interaction between the user and the computer and other aspects of the use case. It should include all the behavior associated with the use case in terms of the mainline sequence, different variations to the normal behavior, the system responses associated with the use case, the exceptional conditions that may occur in the behavior, etc. The behavior description is often written in a conversational style describing the interactions between the actor and the system. The text description may be informal, but some structuring is recommended. The following are some of the information which may be included in a use case text description in addition to the mainline sequence, and the alternative scenarios. Contact persons: This section lists the personnel of the client organization with whom the use case was discussed, date and time of the meeting, etc. Actors: In addition to identifying the actors, some information about actors using this use case which may help the implementation of the use case may be recorded. Pre-condition: The preconditions would describe the state of the system before the use case execution starts. Post-condition: This captures the state of the system after the use case has successfully completed. Non-functional requirements: This could contain the important constraints for the design and implementation, such as platform and environment conditions, qualitative statements, response time requirements, etc. Exceptions, error situations: This contains only the domain-related errors such as lack of user’s access rights, invalid entry in the input fields, etc. Obviously, errors that are not domain related, such as software errors, need not be discussed here. Sample dialogs: These serve as examples illustrating the use case. Specific user interface requirements: These contain specific requirements for the user interface of the use case. For example, it may contain forms to be used, screen shots, interaction style, etc. Document references: This part contains references to specific domain-related documents which may be useful to understand the system operation Example 2: A supermarket needs to develop the following software to encourage regular customers. For this, the customer needs to supply his/her residence address, telephone number, and the driving license number. Each customer who registers for this scheme is assigned a unique customer number (CN) by the computer. A customer can present his CN to the checkout staff when he makes any purchase. In this case, the value of his purchase is credited against his CN. At the end of each year, the supermarket intends to award surprise gifts to 10 customers who make the highest total purchase over the year. Also, it intends to award a 22 caret gold coin to every customer whose purchase exceeded Rs.10,000. The entries against the CN are the reset on the day of every year after the prize winners’ lists are generated. 62 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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