See Converting Numbers To Words Part I.
The next test will test 20-99. I think in real TDD, you’re supposed to write tests that test just one thing. But I’m not doing real TDD, so I’m testing in groups.
Debug.Assert NumbersToWords(20) = "twenty"
Debug.Assert NumbersToWords(21) = "twenty-one"
Debug.Assert NumbersToWords(30) = "thirty"
Debug.Assert NumbersToWords(77) = "seventy-seven"
Debug.Assert NumbersToWords(99) = "ninety-nine"
End Sub
Again, I’m testing the edges and few in between. Now that I have two test procedures, I’ll need to create a procedure to run them both.
TEST_Singles
TEST_Tens
Debug.Print "tests passed"
End Sub
Now I can run TEST_All and make sure I don’t break any previous tests with the changes I make. Of course, TEST_Tens fails so it’s time to write some code to make it pass. I tried to write the simplest code possible, but it didn’t work out for me.
Dim vaSingles As Variant
Dim vaTens As Variant
Dim sReturn As String
vaSingles = Split("zero,one,two,three,four,five,six,seven,eight,nine,ten,eleven,twelve,thirteen,fourteen,fifteen,sixteen,seventeen,eighteen,nineteen", ",")
vaTens = Split("NA,NA,twenty,thirty,forty,fifty,sixty,seventy,eighty,ninety", ",")
If dNumbers > 19 Then
sReturn = vaTens(dNumbers \ 10) & "-" & vaSingles(dNumbers – ((dNumbers \ 10) * 10))
Else
sReturn = vaSingles(dNumbers)
End If
NumbersToWords = Trim$(sReturn)
End Function
That fails because NumbersToWords(20) returns twenty-zero. So there’s a special case that needs to be handled.
Dim vaSingles As Variant
Dim vaTens As Variant
Dim sReturn As String
vaSingles = Split("zero,one,two,three,four,five,six,seven,eight,nine,ten,eleven,twelve,thirteen,fourteen,fifteen,sixteen,seventeen,eighteen,nineteen", ",")
vaTens = Split("NA,NA,twenty,thirty,forty,fifty,sixty,seventy,eighty,ninety", ",")
If dNumbers > 19 Then
sReturn = vaTens(dNumbers \ 10)
If dNumbers Mod 10 <> 0 Then
sReturn = sReturn & "-" & vaSingles(dNumbers – ((dNumbers \ 10) * 10))
End If
Else
sReturn = vaSingles(dNumbers)
End If
NumbersToWords = Trim$(sReturn)
End Function
That works. But I can see this special case handling becoming a problem. Maybe. We’ll see what happens when we test in the hundreds.
