3.4 Special Logical Relationships

The Class/Instance Relationship

Another tool that helps us understand and manage complexity is the class/instance relationship. The term “class/instance relationship” is more commonly used in software than in hardware. A class is a construct that describes the general features of something, and an instance is a specific occurrence of the class. The instance is often referred to as the instantiation of the class.

The idea of class/instance is quite common. For example, if we referred to a model of a car (say, a Ford Explorer), that is the class, and an instance would be a specific Vehicle Identification Number (VIN). A part number refers to a class, and a serial number refers to an instance. In many computer languages, ...

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