VBScript in a Nutshell

Name

Randomize Statement

Syntax

Randomize [number]

number

Use: Optional

Data Subtype: Numeric

Any valid numeric expression.

Description

Initializes the random number generator.

Rules at a Glance

• Randomize uses number as a new seed value to initialize the random number generator used by the Rnd function. The seed value is an initial value that generates a sequence of pseudo-random numbers.

• If you don’t pass number to the Randomize statement, the value of the system timer is used as the new seed value.

• Repeatedly passing the same number to Randomize doesn’t cause Rnd to repeat the same sequence of random numbers.

• If Randomize is not used and the Rnd function is called either with no argument or with 1 as an argument, the Rnd function always uses the same number as the seed value the first time it is called, and subsequently uses the last generated number as a seed value.

Programming Tips & Gotchas

If you need to repeat a sequence of random numbers, you should call the Rnd function with a negative number as an argument immediately prior to using Randomize with any numeric argument. This is illustrated in the example program.

Example

Public Sub RepeatNumbers( )

dim arr(9,3)
dim loopCtr, intctr
dim strMsg

for loopCtr = 0 to 3
   Rnd(-1)
   Randomize(100)
   for intCtr = 0 to 9
      strMsg = strMsg & rnd( ) & " "
   next
   strMsg = strMsg & vbcrlf
next

MsgBox strMsg

End Sub

See Also

Rnd Function