Visual Basic Language Reference  

Rnd Function

Returns a random number of type Single.

Rnd[(number)]

Parameter

number
Optional. A Single value or any valid Single expression.

Return Values

If number is Rnd generates
Less than zero The same number every time, using number as the seed.
Greater than zero The next random number in the sequence.
Equal to zero The most recently generated number.
Not supplied The next random number in the sequence.

Remarks

The Rnd function returns a value less than 1, but greater than or equal to zero.

The value of number determines how Rnd generates a random number:

For any given initial seed, the same number sequence is generated because each successive call to the Rnd function uses the previously generated number as a seed for the next number in the sequence.

Before calling Rnd, use the Randomize statement without an argument to initialize the random-number generator with a seed based on the system timer.

To produce random integers in a given range, use this formula:

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

Here, upperbound is the highest number in the range, and lowerbound is the lowest number in the range.

Note   To repeat sequences of random numbers, call Rnd with a negative argument immediately before using Randomize with a numeric argument. Using Randomize with the same value for number does not repeat the previous sequence.

Example

This example uses the Rnd function to generate a random integer value from 1 to 6.

Dim MyValue As Integer
MyValue = CInt(Int((6 * Rnd()) + 1)) ' Generate random value between 1 and 6.

See Also

Math Summary | Randomize Statement