Task

The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.

Show output for n = 1000.

This is is the same as Project Euler problem 1.

Extra credit: do this efficiently for n = 1e20 or higher.




Declare function mulsum35(n as integer) as integer
Function mulsum35(n as integer) as integer
    Dim s as integer
    For i as integer = 1 to n - 1
        If (i mod 3 = 0) or (i mod 5 = 0) then
            s += i
        End if
    Next i
    Return s
End Function
Print mulsum35(1000)
Sleep
End