Hi,

This is not a pure F# question, but I am pulling my hair out and any hint would be greatly appreciated.

I am trying to learn F# by using it to solve Project Euler problems while reading Robert's book. Problem 17 asks for the total number of characters (excluding spaces and hyphens) in the numbers "one" to "one thousand".

I think my code works, but my answer is incorrect. Am I missing something obvious?

**** Start of Code ****
#light

let rec GetCount x =
if (x < 20) then //first the singles and teens
match x with
|1 -> "one".Length
|2 -> "two".Length
|3 -> "three".Length
|4 -> "four".Length
|5 -> "five".Length
|6 -> "six".Length
|7 -> "seven".Length
|8 -> "eight".Length
|9 -> "nine".Length
|10 -> "ten".Length
|11 -> "eleven".Length
|12 -> "twelve".Length
|13 -> "thirteen".Length
|14 -> "fourteen".Length
|15 -> "fifteen".Length
|16 -> "sixteen".Length
|18 -> "eighteen".Length
|19 -> "nineteen".Length
|_ -> 0
elif (x < 100) then
match (x/10) with //now the -ties
|2 -> GetCount(x%10) + "twenty".Length
|3 -> GetCount(x%10) + "thirty".Length
|4 -> GetCount(x%10) + "forty".Length
|5 -> GetCount(x%10) + "fifty".Length
|6 -> GetCount(x%10) + "sixty".Length
|7 -> GetCount(x%10) + "seventy".Length
|8 -> GetCount(x%10) + "eighty".Length
|9 -> GetCount(x%10) + "ninety".Length
|_ -> 0
elif (x < 1000) then
if (x % 100 = 0) then (GetCount(x/100) + "hundred".Length) //n hundred (without and...)
else (GetCount(x/100) + "hundred and".Replace(" ","").Length + GetCount(x % 100)) //n hundred and m
elif (x = 1000) then "one thousand".Replace(" ","").Length
else 0;;

{1 .. 1000} |> Seq.fold (fun acc x -> acc + GetCount(x)) 0;;
**** End of Code ****

Thanks!