Recursion in F#
- by MarkPearl
Things are slowly coming together – I was able to look at a bit of F# code and intuitively know what it was going to do (yay)… So today I saw a blog post by Bob Palmer on Fibonacci numbers in F# which inspired me to look at bit into recursion. First the C# example… class Program
{
public static void CountDown(int n)
{
switch (n)
{
case 0: Console.WriteLine("End of Count");
break;
default:
Console.WriteLine(n);
CountDown(n-1);
break;
}
}
static void Main(string[] args)
{
CountDown(10);
Console.ReadLine();
}
}
In F#, the equivalent would look something like this…
open System
let rec CountDown n =
match n with
| 0 -> Console.WriteLine("End of Count");
| n -> Console.WriteLine(n); CountDown (n-1);
CountDown 10
Console.ReadLine()
Pretty simple stuff. With F# you when making recursive calls you need to explicitly declare that the function is recursive with the “rec” keyword. Otherwise the code is pretty easy to read and self explanatory.
