How do i generate normal and exponential distribution of customer

I have searched many link and could not get an idea. My program is used to simulate customer occurences in the store. The number of customer is predetermined by the user and it will let me generate a uniform, normal and exponential distribution throughout the number of days of the simulation.

Dim daysplit(days) As Integer
    Dim quotient As Integer
    quotient = Math.Floor(custcount / days)
    remainder = custcount Mod days
    Dim currenttotal As Integer = 0
    For k As Integer = 1 To days
        daysplit(k) = If(k < remainder, quotient + 1, quotient)
        daysplit(k) = quotient
        currenttotal += quotient
    Next
    For l As Integer = 1 To days
        If (currenttotal < custcount) Then
            daysplit(l) += 1
            remainder -= 1
            currenttotal += 1
        End If
    Next

The code is used to generate the uniform distribution. How do i generate normal distribution and exponential distribution with a given sum.