Find duplicate characters in a string

In this post we will see how to find duplicate characters in a string.For example we can identity how many times character S occurs in a string.

using System;

using System.Collections.Generic;

public class Program
{
public static void Main()
{
string temp="SHUKLAA";
Dictionary<char,bool> chars=new Dictionary<char,bool>();
foreach(char ch in temp)
{
if(!chars.ContainsKey(ch))
chars.Add(ch,true);
else
Console.WriteLine(string.Format("duplicate character is {0}",ch))

}

}
};

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