Help in in program

Dear
Try this code:
namespace problem
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = "AbcdeaDFGfAf";
            char ch;
            int k,j=0;
            int count=0,count1=0;
            Console.Clear();
            for(ch='A';ch<='Z';ch++,j=0)
            {
                count=count1=0;
                for(j=0;j                {
                    if(str[j]==ch)
                        count++;
                    if(str[j]==(ch+32))
                        count1++;
                }
                if(( count>=2|| count1>=2)|| (count+count1)>=2)
                {
                    for(k=1;k<=count;k++)
                        Console.Write(ch);
                    for (k = 1; k <= count1; k++)
                        Console.Write(char.ToLower(ch));
                    Console.WriteLine();
                }
            }
        }
    }
}
Thanks
Happy Coding

Thank you sir.....Its working fine and helped me a lot to learn many new concept.

Thanks&Regards,
Habib

static void Test1()

{

// Ascii Code For 'A' = 65

// Ascii Code For 'B' = 66

// and so on...

// Ascii Code For 'Z' = 90

// Ascii Code For 'a' = 97

// Ascii Code For 'b' = 98

// and so on...

// Ascii Code For 'z' = 122

Hashtable characterTable = new Hashtable();

// initialize characterTable with keys 'A' to 'Z' having empty values.

for (int index=65; index<=90; index++)

{

characterTable.Add(index, "");

}

//string input = "AbcdeaDFGfAf";

Console.WriteLine("Input:\n");

string input = Console.ReadLine();

int asciiCode = 0;

int lowerCaseAsciiCode = 0;

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

{

// check if it's a character because we're only interested in characters. A-Z,a-z.

if (char.IsLetter(input[i]))

{

// ascii codes for characters are either 65-90 (A-Z), or 97-122 (a-z)

asciiCode = input[i];

// check if it's uppercase

if (asciiCode <= 90)

{

characterTable[asciiCode] = input[i] + characterTable[asciiCode].ToString();

}

else

{

// it's lower case

lowerCaseAsciiCode = asciiCode - 32;

characterTable[lowerCaseAsciiCode] = characterTable[lowerCaseAsciiCode].ToString() + input[i];

}

}

}

Console.WriteLine();

// display output

for (int j = 65; j <= 90; j++)

{

string letters = characterTable[j] as string;

if (letters.Length > 1)

{

Console.WriteLine(letters);

}

}

Console.Read();

}