private String translatePos(int row, int col) {
      if (row < RowNum && col < ColNum && row >= 0 && col >= 0) {
         // if the row and column number is valid for our grid
         StringBuilder str = new StringBuilder();
         str.append("");
         str.append((char)('A' + col));
         if (row < 9) {
            str.append((char)('1' + row));
         }
         else {
            str.append('1');
            str.append((char)('0' + row - 9));
         }
         return str.toString();
      }
      else {
         throw new RuntimeException("Position invalid!\n");
      }
   }