Faster Smarter Beginning Programming

Generating Random Numbers

Visual Basic .NET provides exactly one random number generator, a function named Rnd() that returns a pseudo-random Double between 0 and 1. After the following statements execute, the dblWhoKnows variable contains a random number between 0 and 1:

Dim dblWhoKnows As Double
dblWhoKnows = Rnd()

If you need random numbers in a different range, such as 25 to 75, just multiply the Rnd() result by the difference and add the starting value. In the following expression, (Rnd() * 50) returns a random number between 0 and 50. Adding an offset of 25 makes the complete expression return a value in the desired range:

25 + (Rnd() * 50)

The Rnd() function never returns a result of exactly 0 or exactly 1. As a result, the expression

Int(Rnd() ...