Word checker

Example:

string input = "the elephant jumps on the ball".ToLower();

string[] words = input.Split(' ','.',',');

List<string> unikWords = new List<string>();
List<int> count = new List<int>();

foreach (string value in words)
{
if (unikWords.Contains(value))
{
int p = unikWords.IndexOf(value);
count[p]++;
}
else
{
unikWords.Add(value);
count.Add(1);
}
}

for (int i = 0; i < unikWords.Count; i++)
{
if (count[i] > 1)
MessageBox.Show(unikWords[i]+","+count[i].ToString());
}

Dictionary<string,int> dict= new Dictionary<string,int>();
string str = "the elephant jumps on the ball";
string [] a = str.Split(new char []{' '});
foreach( string s in a)
{
  if (dict.ContainsKey(s) )
     dict[s]++;
  else
     dict[s]=1;
}
foreach(string k in dict.Keys)
{
  if (dict[k] == 2) Console.WriteLine(k);
}

:)

A first attempt would be just to split every line in words and then sort the resulting list. After that you just loop over the list and check if a word is followed once or more times by itself..

Maybe not very efficient, but quite easy.