RANDOMISE

Syntax

RANDOMISE [(start)] or

RANDOMISE \ (Minerva v1.82+ only)

Location QL ROM

SuperBASIC uses a standard method to generate pseudo random numbers.

Each time that the function RND is called, a start value specified by the command RANDOMISE is multiplied by a large number and another number is added, the solution is modulated and the final number is nearly unpredictable.

This method means that after a RANDOMISE command with parameter, RND will always generate the same numbers. If you pick another number as the parameter (or do not specify a parameter at all), this will let RND produce other numbers. If no parameter is specified, RANDOMISE calculates a random number by combining some internal system data such as the time, date, pointers etc.

Example

100 RANDOMISE 38
110 FOR n=1 TO 10: PRINT RND(10)

The program will always write the same ten random numbers on the screen.

MINERVA NOTE

The main problem with using RANDOMISE is that even without a parameter, the same pattern of ‘random’ numbers is generated if the interval between when the computer is switched on and when the line containing RANDOMISE is reached tends to be the same every time that a program is run. Although v2.53+ of SMS makes RANDOMISE without a parameter more random, the only other fix is on v1.82+ of Minerva which allows you to use:

RANDOMISE \

instead of the normal RANDOMISE which should alleviate this problem somewhat.

CROSS-REFERENCE

RND is the function that returns a random number. RANDOMISE influences MATRND in the same way.