Code Golf: Prime Factors of a Number [closed]

Answer 1

C#, 366 characters

C# is not the most averbose language for something like this, but this is quite compact:

class P {
   static void Main(string[] a) {
      int i = int.Parse(a[0]);
      var p = new System.Collections.Generic.List();
      for (int n = 2; i > 1; n++)
         if (p.Find(q => n % q == 0) == 0) {
            p.Add(n);
            while (i % n == 0) {
               System.Console.WriteLine(n);
               i /= n;
            }
         }
   }
}

Edit:
I saw that Noldorin used the List.Find method in his F# code, and realised that it would be a bit shorter than a foreach...

Edit:
Well, if it doesn't have to be a complete program...

C#, 181 characters

string f(int i) {
   var r = "";
   var p = new System.Collections.Generic.List();
   for (int n = 2; i > 1; n++)
      if (p.Find(q => n % q == 0) == 0) {
         p.Add(n);
         while (i % n == 0) {
            r += "x" + n;
            i /= n;
         }
      }
   return r.Substring(1);
}

Compressed:

string f(int i){var r="";var p=new System.Collections.Generic.List();for(int n=2;i>1;n++)if(p.Find(q=>n%q==0)==0){p.Add(n);while(i%n==0){r+="x"+n;i/=n;}}return r.Substring(1);}