using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter the PLAIN text:");

        string plain = Console.ReadLine().ToUpper();

        plain = plain.Replace(" ","");

        Console.WriteLine("Enter the KEY text:");

        string key =  Console.ReadLine().ToUpper();

        key = key.Replace(" ","");

        char[,] matrix = new char[5,5];

​

        for(int i=0; i<5; i++)

        {

            for(int j=0; j<5; j++)

            {

                matrix[i,j] = Convert.ToChar( 33 );

            }

        }

        initializeMatrix(matrix,key,73,72);

        //Reformat input plain text

        for(int i=0; i<plain.Length-1; i+=2)

        {

            if(plain[i] == plain[i+1])

            {

                plain = plain.Insert(i+1,"X");

            }

        }

        if(!(plain.Length % 2 == 0))

        {

            plain = plain +  "X";

        }

        //playfair logic

        for(int k=0; k<plain.Length-1; k=k+2)

        {

            for(int i=0; i<5; i++)

            {

                for(int j=0; j<5; j++)

                {

                }

            }

        }

        Console.WriteLine("PlainText = "+ plain);

    }

​

    public static void initializeMatrix(char[,] matrix,string key, int equal1, int equal2)

    {

        //Fill matrix

            int len = key.Length;

            bool charThere = false;

            bool charAdded = false;

            for(int k=0; k<key.Length; k++)

            {

                charThere = false;

                charAdded = false;

                for(int i=0; i<5; i++)

                {

                    if(!(charThere || charAdded))

                    {

                        for(int j=0; j<5; j++)

                        {

                            if(matrix[i,j] == key[k])

                            {

                                //Console.WriteLine("Char found");

                                charThere = true;

                                break;

                            }

                            else if(matrix[i,j] == Convert.ToChar( 33 ))

                            {

                                //Console.WriteLine("k value is :"+k+" "+key[k]);

                                if(key[k] == Convert.ToChar(equal1))

                                {

                                    matrix[i,j] = Convert.ToChar(equal2);

                                }

                                else

                                {

                                    matrix[i,j] = key[k];   

                                }

                                charAdded = true;

                                break;

                            }

                        }

                    }

                    else

                    {

                        break;

                    }

                }   

            }

            //For remaining alphabates

            bool charfound = false;

            bool charput = false;

            for(int k=65; k<91;k++)

            {

                if(k != equal1)

                {

                    charfound = false;

                    charput = false;

                    for(int i=0; i<5; i++)

                    {

                        if(!(charfound || charput))

                        {

                            for(int j=0; j<5; j++)

                            {

                                if(matrix[i,j] == Convert.ToChar(k))

                                {

                                    charfound = true;

                                    break;

                                }

                                else if(matrix[i,j] == Convert.ToChar( 33 ))

                                {

                                    matrix[i,j] = Convert.ToChar(k);

                                    charput = true;

                                    break;

                                }

                            }

                        }

                        else

                            break;

                    }

                }

            }

            //Printing the matrix

            for(int i=0; i<5; i++)

            {

                for(int j=0; j<5; j++)

                {

                    Console.Write(matrix[i,j]+" ");

                }

                Console.Write("\n");

            }

    }

}