Write a program to find the duplicate characters in a string.

Solution:

using System;

namespace CharOccuerance
{
    class Program
    {
        static void Main()
        {
            Console.WriteLine("Enter a string:");
            var str = Console.ReadLine();
            var charArray = str.ToCharArray();

            Console.WriteLine("Duplicate Char:");
            for (var i = 0; i < charArray.Length; i++)
            {
                var count = 1;
                for (var j = i + 1; j < charArray.Length; j++)
                {
                    if (charArray[i] != charArray[j] || charArray[i] == ' ') continue;
                    count++;
                    charArray[j] = '0';
                }

                if (count > 1 && charArray[i] != '0')
                    Console.WriteLine(charArray[i]);
            }
            Console.ReadLine();
        }
    }
}