HEELPBOOK - How to generate a number between 2 other numbers (Visual Basic) #####################

The question is: "How can I generate a number between 2 other numbers?"

The main problem with this is that many people haven't realised that the Rnd function returns a value less than 1 BUT greater than or equal to zero (0<=Rnd<1).

So since most people think that the Rnd function can generate the number 1, the algorithms they use are incorrect. The correct way is this:



Int((upperbound - lowerbound + 1) * Rnd + lowerbound)



Which can easily be put into a function:



Private Function RandomInteger(Lowerbound As Integer, Upperbound As Integer) As Integer

    RandomInteger = Int((Upperbound - Lowerbound + 1) * Rnd + Lowerbound)

End Function



...and an example of using it is:



Private Function RandomInteger(Lowerbound As Integer, Upperbound As Integer) As Integer

    RandomInteger = Int((Upperbound - Lowerbound + 1) * Rnd + Lowerbound)

End Function

Private Sub Form_Load()

    Randomize 'Just once to start getting random numbers

    MsgBox RandomInteger(1, 52)

End Sub



The code above would be used most of the times for a card game, to draw a card at random. If we set Lowerbound=1 and Upperbound=6 then we would have ourselves dice rolling code.


############ ARTICLE INFO #############

Article Month: November
Article Date: 13/11/2012
Permalink: http://heelpbook.altervista.org/2012/how-to-generate-a-number-between-2-other-numbers-visual-basic/
Source: http://www.vbforums.com/showthread.php?281172-Tutorial-Random-Numbers-VB6-and-earlier
Language: English

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