Users of object-oriented technology usually think of classes as containing the information necessary to create instances, i.e., the structure and capabilities of an instance is determined by its corresponding class. There are three commonly used (and different) views on the definition for “class”: A class is a pattern, template, or blueprint for a category of structurally identical items. The items created using the class are called instances.
This is often referred to as the “class as a cookie cutter'” view. As you might guess, the instances are the “cookies.” A class is a thing that consists of both a pattern and a mechanism for creating items based on that pattern. This is the “class as aninstance factory’” view; instances are the individual items that are “manufactured” (created) using the class’s creation mechanism. A class is the set of all items created using a specific pattern. Said another way, the class is the set of all instances of that pattern SUPER CLASS The parent class by identifying things called objects. Object a real person, place, event or transaction.
For example, when a patient makes an appointment to see a doctor, the patient is an object, the doctor is an object oriented analysis is an object model, which represents the informationconcepts. c) A modular approach saves money and time, because the modules can be optimized, tested and reused. c) The black box concept is an example of encapsulation. Which means that all data and methods are selfcontained. A black box doesnot want or need outside interference. the system because objects send and receive messages but donot alter the internal methods of the other objects. 6. a) Answer. Diagram 0 DFD is called an exploded DFD. Diagram 0 system as a single Present vs future constraints-
The new system must interact with existing system i.e. the constraint something that must be met as soon as the system is developed or modified. system must be installed by the end of the December in order to meet government reporting rules , cost must be within the budgeted amount. So , it is an instance of Present vs future constraints. Internal constraints: Vice President of Finance insists on approving the final designs and Constraints due to the requirements within the organizations. b) In order to make everyone agree to the project , preliminary investigations should be done which consists of six steps. Understanding the problem or opportunity,define the project scope and the constraints,perform fact finding,estimate project benefits,estimate project development time cost, present result and recommendations to management. c) Tangible benefits:
The new system would reduce the clercal time and errors, and avoid possible fines and penalties for non-compliance. Intangible benefits: A user friendly system to improve the moral of the pay role departments. d) The format of the preliminary investigation report varies from one company to another. But a typical reportare: Outputs,Inputs, employees security at the operating systemI also must consider data retention requirements and determine whether data can be deleted or achieved on a specific timetable.
Even for printing of the customer statements I need to know the number of active accounts and have a forecast for one ,two or five years because information affects the future decisions. d) TCO: I costs I must identify and document indirect expenses that contribute to the total cost of ownership. That can be done through accessing various alternatives. After considering the indirect as well as hidden costs a system that seems inexpensive initially might actually turn out to be the most costly choice. Indirect costs such as user peer and self support and downtime productivity losses typically were not included in the IT department budgets and were unaccounted for most of the companies.
