BASIC stamp manual v2.2

5: BASIC Stamp Command Reference – RANDOM

BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com • Page 359

RANDOM

BS1 BS2 BS2e BS2sx BS2p BS2pe BS2px

RANDOM Variable

Function

Generate a pseudo-random number.

• Variable is a variable (usually a word) whose bits will be scrambled

to produce a random number. Variable acts as RANDOM's input

and its result output. Each pass through RANDOM stores the next

number, in the pseudorandom sequence, in Variable.

Explanation

RANDOM generates pseudo-random numbers ranging from 0 to 65535.

They’re called “pseudo-random” because they appear random, but are

generated by a logic operation that uses the initial value in Variable to "tap"

into a sequence of 65535 essentially random numbers. If the same initial

value, called the "seed", is always used, then the same sequence of

numbers is generated. The following example demonstrates this:

SYMBOL result = W1

Main:

result = 11000

RANDOM result

DEBUG result

GOTO Main

-- or --

result VAR Word

Main:

result = 11000

RANDOM result

DEBUG DEC ? result

GOTO Main

In this example, the same number would appear on the screen over and

over again. This is because the same seed value was used each time;

specifically, the first line of the loop sets result to 11,000. The RANDOM

command really needs a different seed value each time. Moving the

"result =" line out of the loop will solve this problem, as in:

All