//Q: Determine if string has all unique characters. 

using System;

public class Program

{

    public static void Main()

    {

        string x = "xyswre";

        isUnique(x);

    }

    private static void isUnique(String x)

    {

        char[] y = x.ToCharArray();

        for(int i=0; i < y.Length; i++){

            for(int j= i + 1; j < y.Length;j++){

                if(x[i]==y[j])

                {

                    Console.WriteLine("duplicate character is " + y[j]);

                }

            }

        }

    }

}