This final part completes the story and largely describes the predefined library and other material which enable the Ada program to communicate with various aspects of its environment.

In essence the predefined environment comprises the four packages Standard, Ada, System and Interfaces. Chapters 23 and 24 cover Standard and Ada which are essentially independent of the underlying system whereas Chapter 25 covers System and Interfaces which very much depend upon the underlying system. The discussions in Chapters 23 and 24 are reasonably comprehensive and cover all the points necessary for normal use; the container library is rather large and has been factored off into Chapter 24. The discussion in Chapter 25 is less thorough because it depends upon the implementation.

Chapters 23 and 25 are each followed by a complete program. The first illustrates the use of the string handling and random number generation features provided by the predefined library and the second illustrates how users can provide their own storage pools.

Chapter 26 is an overview of the scope of the six specialized annexes. Although this book does not attempt serious coverage of these annexes nevertheless a brief overview of their scope seems appropriate. In particular enough information is given to use the complex number and vector and matrix facilities of the Numerics annex. Some material on task termination and timers from the Systems Programming and Real-Time annexes was covered in detail in Chapter 22.

The final Chapter 27 pulls together a small number of loose threads, considers the problems of portability and some thoughts on matters such as design and the construction of programs from components and concludes with an introduction to SPARK.

There are then three appendices. Appendix 1 lists the reserved words, attributes, aspects, pragmas, and restrictions; Appendix 2 contains a brief glossary; and Appendix 3 gives the complete syntax plus index.

The book concludes with answers to selected exercises; the reader is encouraged to study these and especially any discussion which often covers minor but nevertheless important points. Note that the answers to all the exercises and other supplementary material will be found on the web.