How can you remove duplicate characters in a string?

Question

I have to implements a function that takes a string as an input and finds the non-duplicate character from this string.

So an an example is if I pass string str = \"

Answer 1

namespace Demo { class Program {

  static void Main(string[] args) {
     string myStr = "kkllmmnnouo";
     Console.WriteLine("Initial String: "+myStr);
    // var unique = new HashSet(myStr);
     HashSet unique = new HashSet(myStr);
     Console.Write("New String after removing duplicates: ");

     foreach (char c in unique) 
        Console.Write(c);   
  }    } }