Rnd Function

   
Rnd Function

Class

Microsoft.VisualBasic.VBMath

Syntax

 Rnd[(   number   )] 
number (optional; Single)

Any valid numeric expression that serves as a seed value

Return Value

A Single data type random number

Description

Returns a random number

Rules at a Glance

  • The behavior of the Rnd function is determined by number , as described in the following table:

Number

Rnd generates

< 0

The same number each time, using seed as the seed number

> 0

The next random number in the current sequence

The most recently generated number

Not supplied

The next random number in the current sequence

  • The Rnd function always returns a value between and 1.

  • If number is not supplied, the Rnd function will use the last number generated as the seed for the next generated number. This means that given an initial seed (seed), the same sequence will be generated if number is not supplied on subsequent calls.

Example

The following example uses the Randomize procedure along with the Rnd function to fill 100 cells of an Excel worksheet with random numbers . It requires that a reference to the Microsoft Excel Object Library be added to the project. It also leaves the instance of Excel running once the code has finished execution.

 Public Sub GenerateRandomNumbers(  )       Dim oApp As New Excel.Application(  )       Dim objSheet As Excel.Worksheet       Dim intRow, intCol As Integer       oApp.Visible = True       objSheet = oApp.Workbooks.Add.Worksheets(1)       Randomize(  )       ' Set the color of the input text to blue       objSheet.Cells.Font.ColorIndex = 5       ' Loop through first 10 rows & columns,        ' filling them with random numbers       For intRow = 1 To 10          For intCol = 1 To 10             objSheet.Cells(intRow, intCol).Value = Rnd(  )          Next       Next       ' Resize columns to accommodate random numbers       objSheet.Columns("A:C").AutoFit(  )       objSheet = Nothing    End Sub 

Programming Tips and Gotchas

  • Before calling the Rnd function, you should use the Randomize procedure to initialize the random-number generator.

  • The standard formula for producing numbers in a given range is as follows :

     Int((   highest   -   lowest   + 1) * Rnd +   lowest   ) 

    where lowest is the lowest required number in the range and highest is the highest.

See Also

Randomize Procedure

   


VB.Net Language in a Nutshell
VB.NET Language in a Nutshell
ISBN: B00006L54Q
EAN: N/A
Year: 2002
Pages: 503

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