public static Board readFromFile(string path)
{
if (!File.Exists(path))
{
throw new Exception("ERROR: Specified sudoku puzzle file does not exist: " + path);
}
string[] lines = File.ReadAllLines(path).Where(line => line.Length > 0).ToArray(); // Ignore empty lines
if (lines.Length < 3)
{
throw new Exception("ERROR: Specified sudoku puzzle file does not have at least three lines: " + path);
}
int size = Int32.Parse(lines[0]);
string[] characterStrings = lines[1].Split(null);
if (lines.Length - 2 != size)
{
throw new Exception(
"ERROR: Specified sudoku puzzle file puzzle size does not match the number of characters provided: " + path);
}
if (characterStrings.Any(characterString => characterString.Length != 1))
{
throw new Exception(
"ERROR: Specified sudoku puzzle file does not have characters with length equal to one: " + path);
}
CharSet validChars = new CharSet();
foreach (string characterString in characterStrings)
{
if (validChars.contains(characterString[0]))
{
throw new Exception(
"ERROR: Specified sudoku puzzle file character header has duplicate characters: " + path);
}
validChars.insert(characterString[0]);
}
Board sudokuBoard = new Board(size, validChars);
for (int i = 2; i < lines.Length; ++i)
{
List <char> row = lines[i].ToCharArray().Where(c => c != ' ').ToList();
if (row.Count != size)
{
throw new Exception(
"ERROR: Specified sudoku puzzle file contains one or more lines with an incorrect numbers of characters: " + path);
}
int j = 0;
foreach (char cell in row)
{
if (!sudokuBoard.isValidChar(cell))
{
throw new Exception(
"ERROR: Specified sudoku file " + path + " contains an invalid character in its board: " + lines[i][j]);
}
sudokuBoard.setCell(i - 2, j, cell);
++j;
}
}
return(sudokuBoard);
}