CRC cards are used to describe in an informal fashion the responsibilities and collaborators for a class. Figure 1 shows a typical CRC card.

Figure K.1. Typical CRC Card

Figure 2 shows the UML notation for classes and interfaces. You can optionally supply attributes and methods in a class diagram, as in Figure 3.

Figure K.2. UML Symbols for Classes and Interfaces

Figure K.3. Attributes and Methods in a Class Diagram

Figure K.4. An Aggregation Relationship with Multiplicities

Table 1 shows the arrows used to indicate relationships between classes. Multiplicity can be indicated in a diagram, as in Figure 4.

Table K.1. UML Relationship Symbols

Relationship	Symbol	Line Style	Arrow Tip
Inheritance		Solid	Triangle
Interface Implementation		Dotted	Triangle
Aggregation		Solid	Diamond
Dependency		Dotted	Open

Dependencies between objects are described by a dependency diagram. Figure 5 is a typical example.

Figure K.5. UML Class Diagram for the ATM Simulation

State diagrams are used when an object goes through a discrete set of states that affects its behavior (see Figure 6).

Figure K.6. UML State Diagram for the ATM Class