Which description matches a class diagram?

Which description matches a class diagram?

• A. A diagram showing the sequence of method calls over time.
• B. A diagram that focuses on interactions between objects.
• C. Rectangle with name at top, variables in the middle, and methods in the bottom.
• D. A diagram illustrating state transitions.

Answer: (C)

A class diagram represents the structure of a system by showing classes, their data, and their behavior. The standard notation is a rectangle divided into three compartments: the class name on top, the attributes (variables) in the middle, and the operations (methods) at the bottom. Describing a rectangle with a name at the top, variables in the middle, and methods at the bottom matches this three-part class notation exactly. The other descriptions point to different kinds of diagrams: a diagram showing the sequence of method calls over time is a sequence diagram; a diagram focusing on interactions between objects is an interaction diagram (sequence or communication); and a diagram illustrating state transitions is a state diagram.

A class diagram represents the structure of a system by showing classes, their data, and their behavior. The standard notation is a rectangle divided into three compartments: the class name on top, the attributes (variables) in the middle, and the operations (methods) at the bottom. Describing a rectangle with a name at the top, variables in the middle, and methods at the bottom matches this three-part class notation exactly.

The other descriptions point to different kinds of diagrams: a diagram showing the sequence of method calls over time is a sequence diagram; a diagram focusing on interactions between objects is an interaction diagram (sequence or communication); and a diagram illustrating state transitions is a state diagram.