Scrabble game. Need help with parsing words from tiles.

Hi there

So it sounds like you have a few issues in one to solve. The first problem is how to store your tiles. Your current solution suffers a little from what we often call 'redundant data', in the sense that you're storing the same information in multiple ways. When a user places a new tile, you store it in 2 seperate places, when its really just one informat. In addition, your data is more like a grid rather than a list of strings, so you want to be trying to store your data in a way that reflects that. This is a slightly 'opinion' based problem, but you will find that starting from a good foundation always makes your life easier!

    class GridCell
     {
         public int score_multiplier=1;   //this might be 1 for a normal cell, 2 for a double word scale, 3 for a triple
         public char current_character = ' '; //current character in the cell. a space means empty
     }

     //this stores a grid of 21 by 21 characters
     GridCell[] mygrid = new GridCell[21 * 21];

     //get the cell at a given location
     GridCell GetGridCellAt(int x, int y)
     {
         //note this check to ensure a valid location is passed in. we return null if its invalid
         if (x >= 0 && x < 21 && y >= 0 && y < 21)
             return mygrid[x + y * 21];
         else
             return null;
     }

     //this sets up a new cell at each location
     void InitGrid()
     {
         //first instantiate a new grid cell at each square
         for (int i = 0; i < mygrid.Length; i++)
             mygrid[i] = new GridCell();

         //...here you could setup all the special multipliers, i.e....
         GetGridCellAt(20, 20).score_multiplier = '3';
     }

Here we have the core bits of work - a way of storing each cell (the character it contains AND its multiplier), a function to clear it out and a function to get the cell at a given location. As a handy extra feature, the function to get the cell verifies you asked for a valid location before returning anything, and returns the special value 'null' (means theres nothing here) if you do something invalid.

Now you can begin writing some utility functions to build up the functionality of your grid. To get you started, heres one that iterates over all the neighbours of a cell and tells you if any contain a letter (which might be useful for the specific problem you had)

     //check if any neighbour cells contain a letter
     bool DoAnyNeighbourCellsContainALetter(int x, int y)
     {
         //iterate over each of the neighbours in x and y
         for (int xoffset = -1; xoffset <= 1; xoffset++)
         {
             for (int yoffset = -1; yoffset <= 1; yoffset++)
             {
                 //ignore the middle (thats the tile you passed in!)
                 if (xoffset == 0 && yoffset == 0)
                     continue;

                 //get the neighbour
                 GridCell neighbour = GetGridCellAt(x + xoffset, y + yoffset);
                 if (neighbour != null)
                 {
                     //if it contains a letter, return true
                     if (neighbour.current_character != ' ')
                         return true;
                 }
             }
         }

         //if we got all the way through the neighbours without finding anything, return false
         return false;
     }

To replicate a bit of your existing functionality (should you need it), this one extracts all the letters in a cell and returns them as a string:

     //get a column as a string
     string GetColomnAsAString(int column_number)
     {
         string result = "";
         for (int y = 0; y < 21; y++)
         {
             result = result + GetGridCellAt(column_number, y);
         }
         return result;
     }

You should ultimately be able to do all of your logic using this grid cell structure.

Hope that gets you started - good luck!