Type interval
    lower As Double
    upper As Double
End Type

Function stepAway(x As Double) As interval
    Dim As interval result
    result.lower = x - 0.00000000000001
    result.upper = x + 0.00000000000001
    Return result
End Function

Function safeAdd(a As Double, b As Double) As interval
    Return stepAway(a + b)
End Function

Dim As Double a = 1.2
Dim As Double b = .03
Dim As interval result = safeAdd(a, b)
Print a; " "; b; " "; result.lower; " "; result.upper

Sleep