Recursion via Pascal

Cambridge Computer Science Texts

by J.S. Rohl

This book is devoted to recursion in programming, the technique by which the solution to a problem is expressed partly in terms of the solution to a simpler version of the same problem. Ultimately the solution to the simplest version must be given explicitly. In functional programming, recursion has received its full due since it is quite often the only repetitive construct. However, the programming language used here is Pascal and the examples have been chosen accordingly. It makes an interesting contrast with the use of recursion in functional and logic programming. The early chapters consider simple linear recursion using examples such as finding the highest common factor of a pair of numbers, and processing linked lists. Subsequent chapters move up through binary recursion, with examples which include the Towers of Hanoi problem and symbolic differentiation, to general recursion. The book contains well over 100 examples.

204 pages, Paperback

First published January 1, 1984

Reviews

[Dang-Khoa Le Tan · Rating 5 out of 5]

I did not ex­pect to en­joy Recursion via Pascal by J.S. Rohl this much. The text is con­cise and the code im­ple­men­ta­tions are suc­cinct (I’m look­ing at you, Introduction to Recursive Programming). The con­tent strikes a fine bal­ance be­tween the­ory, analy­sis, and im­ple­men­ta­tion.

Reading this book made me fall in love with Pascal again. I see now how Pascal in­flu­enced Go. The way code is writ­ten is beau­ti­ful and el­e­gant. Fif­teen years ago, I did not ap­pre­ci­ate such beauty. But af­ter a decade work­ing with other lan­guages, I am fond of it again. In fact, this book makes me want to give Nim an­other try. I see Nim as a lovely child of Python and Pascal.

One as­pect I par­tic­u­larly en­joyed: the clas­sic method of an­a­lyz­ing com­plex­ity by count­ing each in­struc­tion’s cost. This ap­proach re­veals per­for­mance sub­tleties that as­ymp­totic analy­sis glosses over.

The last chap­ter on elim­i­nat­ing re­cur­sion is a treat. Not many text­books, as far as I have read, touch the sub­ject this deeply.

Verdict: Highly rec­om­mended. 4.5/5. It is clas­sic, it is fun, and it will im­prove your prob­lem-solv­ing skills.