Task

Show how to spell out a number in English.

You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less).

Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional.



Related task

   Spelling of ordinal numbers.


Public twenties As Variant
Public decades As Variant
Public orders As Variant
 
Private Sub init()
    twenties = [{"zero","one","two","three","four","five","six","seven","eight","nine","ten", "eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen"}]
    decades = [{"twenty","thirty","forty","fifty","sixty","seventy","eighty","ninety"}]
    orders = [{1E15,"quadrillion"; 1E12,"trillion"; 1E9,"billion"; 1E6,"million"; 1E3,"thousand"}]
End Sub
 
Private Function Twenty(N As Variant)
    Twenty = twenties(N Mod 20 + 1)
End Function
 
Private Function Decade(N As Variant)
    Decade = decades(N Mod 10 - 1)
End Function
 
Private Function Hundred(N As Variant)
    If N < 20 Then
        Hundred = Twenty(N)
        Exit Function
    Else
        If N Mod 10 = 0 Then
            Hundred = Decade((N \ 10) Mod 10)
            Exit Function
        End If
    End If
    Hundred = Decade(N \ 10) & "-" & Twenty(N Mod 10)
End Function
 
Private Function Thousand(N As Variant, withand As String)
    If N < 100 Then
        Thousand = withand & Hundred(N)
        Exit Function
    Else
        If N Mod 100 = 0 Then
            Thousand = withand & Twenty(WorksheetFunction.Floor_Precise(N / 100)) & " hundred"
            Exit Function
        End If
    End If
    Thousand = Twenty(N \ 100) & " hundred and " & Hundred(N Mod 100)
End Function
 
Private Function Triplet(N As Variant)
    Dim Order, High As Variant, Low As Variant
    Dim Name As String, res As String
    For i = 1 To UBound(orders)
        Order = orders(i, 1)
        Name = orders(i, 2)
        High = WorksheetFunction.Floor_Precise(N / Order)
        Low = N - High * Order 'N Mod Order
        If High <> 0 Then
            res = res & Thousand(High, "") & " " & Name
        End If
        N = Low
        If Low = 0 Then Exit For
        If Len(res) And High <> 0 Then
            res = res & ", "
        End If
    Next i
    If N <> 0 Or res = "" Then
        res = res & Thousand(WorksheetFunction.Floor_Precise(N), IIf(res = "", "", "and "))
        N = N - Int(N)
        If N > 0.000001 Then
            res = res & " point"
            For i = 1 To 10
                n_ = WorksheetFunction.Floor_Precise(N * 10.0000001)
                res = res & " " & twenties(n_ + 1)
                N = N * 10 - n_
                If Abs(N) < 0.000001 Then Exit For
            Next i
        End If
    End If
    Triplet = res
End Function
 
Private Function spell(N As Variant)
    Dim res As String
    If N < 0 Then
        res = "minus "
        N = -N
    End If
    res = res & Triplet(N)
    spell = res
End Function
 
Private Function smartp(N As Variant)
    Dim res As String
    If N = WorksheetFunction.Floor_Precise(N) Then
        smartp = CStr(N)
        Exit Function
    End If
    res = CStr(N)
    If InStr(1, res, ".") Then
        res = Left(res, InStr(1, res, "."))
    End If
    smartp = res
End Function
 
Sub Main()
    Dim si As Variant
    init
    Samples1 = [{99, 300, 310, 417, 1501, 12609, 200000000000100, 999999999999999, -123456787654321,102003000400005,1020030004,102003,102,1,0,-1,-99, -1501,1234,12.34}]
    Samples2 = [{10000001.2,1E-3,-2.7182818, 201021002001,-20102100200,2010210020,-201021002,20102100,-2010210, 201021,-20102,2010,-201,20,-2}]
    For i = 1 To UBound(Samples1)
        si = Samples1(i)
        Debug.Print Format(smartp(si), "@@@@@@@@@@@@@@@@"); " "; spell(si)
    Next i
    For i = 1 To UBound(Samples2)
        si = Samples2(i)
        Debug.Print Format(smartp(si), "@@@@@@@@@@@@@@@@"); " "; spell(si)
    Next i
End Sub