Thinking in C++ Vol 2 - Practical Programming
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Summary

One reason MI exists in C++ is that it is a hybrid language and couldn t enforce a single monolithic class hierarchy the way Smalltalk and Java do. Instead, C++ allows many inheritance trees to be formed, so sometimes you may need to combine the interfaces from two or more trees into a new class.

If no diamonds appear in your class hierarchy, MI is fairly simple (although identical function signatures in base classes must still be resolved). If a diamond appears, you may want to eliminate duplicate subobjects by introducing virtual base classes. This not only adds confusion, but the underlying representation becomes more complex and less efficient.

Multiple inheritance has been called the goto of the 90s. [132] This seems appropriate because, like a goto, MI is best avoided in normal programming, but can occasionally be very useful. It s a minor but more advanced feature of C++, designed to solve problems that arise in special situations. If you find yourself using it often, you might want to take a look at your reasoning. Ask yourself, Must I upcast to all the base classes? If not, your life will be easier if you embed instances of all the classes you don t need to upcast to.

Thinking in C++ Vol 2 - Practical Programming
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