The following example illustrates a hierarchy for identifying faults in automobiles. At the topmost level is the faults class containing the algorithm for finding faults, and which is inherited by all of the other classes in the hierarchy. At any point, however, a class has the option to override the default search algorithm with one that is specialised for its problem area. The Domain Classes class mechanical. Faulty distributor arm'.
Worn distributor brushes'.
The starter turns but the engine doesnt fire'. The engine has difficulty starting'. The engine cuts out shortly after starting'. The following outputs were taken from a fault diagnosis session.