//given a 2-D matrix representing an image, a location of a pixel in the screen and a colour
  //replace the colour of the given pixel and all adjacent coloured pixels with the colour

  //declare matrix
  string[,] matrix = new string[10, 10];

  //populate matrix
  populate();

  //get location
  Console.WriteLine("enter pixel coordinate eg 2,3");
  string Location = Console.ReadLine();
  int x =Convert.ToInt16(Location.Substring(0, 1));
  int y =Convert.ToInt16(Location.Substring(2, 1));

  //get colour
  Console.WriteLine("enter pixel colour");
  string colour = Console.ReadLine();

  //replace colours
  matrix[x, y] = colour;

  if (x + 1 <= 10) { matrix[x + 1, y] = colour; }
  if (x - 1 >= 0) { matrix[x - 1, y] = colour; }

  if (y + 1 <= 10) { matrix[x, y+1] = colour; }
  if (y - 1 >= 0) { matrix[x, y-1] = colour; }

  //print matrix to check results
  print();

  //populate matrix
  void populate()
  {
      Random rand = new Random();
      string[] alphabet = new string[] { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };

      for (int i = 0; i < 10; i++)
      {
          for (int q = 0; q < 10; q++)
          {
              int select = rand.Next(0, 25);
              matrix[i, q] = alphabet[select];
          }
      }
  }
  //print matrix
  void print()
  {
      for (int i = 0; i < 10; i++)
      {
          for (int q = 0; q < 10; q++)
          {
              Console.Write(matrix[i, q] + " ");
          }
          Console.WriteLine();
      }
  }