Brainteasers for BASIC Computers

C&VG (Computer & Video Games)

Brainteasers For Basic Computers, by Gordon Lee Shiva Publishing Limited ISBN 0 906812 36 4 Price: £4.95 The idea behind this slim volume (124pp) is to offer 50 puzzles which can be solved by writing a fairly short computer program. As the author points out in his introduction, most computer books either offer a manual or a listing of games to be typed in, and they are usually machine specific. In this book, the user is challenged to write a program which will carry out the number crunching task posed by the puzzle. None of the puzzles is claimed to be particularly new or original and puzzle fans will recognise some as being pretty old, such as Cannon Balls, Chuck-a-Luck and The Monkey and the Coconuts. What is new is that the middle, and largest, section of the book gives a program listing, in pretty basic Basic, which indicates one line of attack in achieving the desired result. Thus, by trying a puzzle or two and maybe not getting very far, a study of the listing will give the novice - either to puzzling, or to programming - an easy to follow outline which will be of use in tackling other puzzles. There is a short solution section at the end, which is really there to confirm what your program should have found. The book is neatly laid out and there is a bonus for us all in that the listings are printed properly instead of looking like a distant copy of a listing which has been used to wrap the fish and chips. The puzzles are of just the right type to promote an interest in programming, They do not demand too much mathematics, though a spot of thinking about the range of possible answers may well lead you to write a better program which takes less time. Just before the listing section is a page or two intended to be helpful about using different machines. This is probably the weakest part of the book, though it is clear that the author did not want to be bogged down in a heap of alternatives and "do this on the ZX, that on your Sharp and something else altogether on your Vic". The section doesn't actually help make string handling clear and you will have to know what your machine demands. For instance, in the first listing we get: 130 FOR M = 1 TO 5 140 FOR L = M + 1 TO 6 140 IF C$(M) = C$(L) THEN GOTO 250. It does not mean that C$ is a DIMensioned array but the Mth member of the string is being compared to the Lth. For some machines at least, this would need to be in the form: 140 IF MID$(C$,M,1) = MID$(C$,L,1) THEN 250. This is not mentioned in the help section. So, provided you can understand enough about programming your machine to make these small adjustments, the 50 puzzles, though they may not seem a lot for the cash, will give you many hours at your machine which will require a lot more of you than hitting Z for left, X for right and SPACE to fire! To give you a taste of a book I would warmly recommend as the intelligent person's alternative to zapping invaders, here is one problem, with which that listing extract above is directly concerned... The other Sunday, the hymn numbers on the board appeared as shown. It caught my eye because I saw that all the digits were different. I then noticed that the second hymn number was twice the first, and the third was equal to the first two added together. This made me wonder if there were any other 'sets' of numbers, all different, that could be formed into three, three-digit numbers with this property. 1 9 2 3 8 4 5 7 6