Magic Numbers - M.Loftus (Your Spectrum-Issue 11-Page 69)





This program demonstrates the magical mystery of the ZX Spectrum.

You won't be able to conjure a rabbit out a hat, but you

should be able to dazzle your friends with a clever piece of 

number manipulation.

        You're asked to choose a number between 60 and 4290. Once

you've typed in the mystery number, the Spectrum generates a five

by five grid of seemingly random numbers. You then have to

choose five numbers; as each number's chosen, the row and

column it comes from are erased from the screen, decreasing the

amount of numbers you have to choose from. When all five numbers

have been chosen from the grid, the Spectrum adds them

together and compares the result to the number you chose at the

outset of the program to see if they're the same. And 'Hey 

Presto!' ... they are the same.

        To say more of the program's inner workings would spoil all the

fun. See if you can work it out for yourself ...





Line 1          GO SUBs to the subroutine that prints up the instructions for

                play on-screen.

Lines 100-110   Ask you to input any integer between 60 and 4290. Line 110

                checks that your answer is valid.

Lines 120-280   Print up the grid of numbers on-screen.

Lines 290-480   Ask you to select a number by its index letter. This number is

                added to the total number of selected numbers, and the

                colour of all the numbers in that row and column are

                changed.

Lines 490-620   This routine transfers the number left and totals selected

                numbers. Funnily enough, the total always comes out as

                your original number ... don't ask me, I'm as stumped as you

                probably are!

Lines 1000-1100 This is the subroutine that prints up the instructions for play

                on-screen. Line 1090 generates a keyboard 'blip'.



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TYPE: Utility 



COMMENT: 





This info file was typed by Jim Grimwood



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