April 2007

Program sudoku.exe calls a file sudoku.dat which holds a sudoku matrix
for solving. For empty (unfilled) cells sudoku.dat has "0" (zeros).
Input format is fixed (two positions for an each number)

Here is an example
 0 0 9 8 0 0 0 0 6
 0 0 6 0 0 4 0 1 0
 4 0 0 0 0 2 0 0 0
 0 5 0 0 8 0 0 3 1
 0 0 1 0 0 0 5 0 0
 2 8 0 0 5 0 0 7 0
 0 0 0 2 0 0 0 0 9
 0 6 0 7 0 0 1 0 0
 5 0 0 0 0 8 6 0 0

Program Sudoku (version April 2007)
1. reads data from the file "sudoku.dat"
2. checks the data for consistency and print original matrix
3. looks for solutions using one or all 3 methods
   method 1: looks for cells with "one only possible number" and fills
             that cell in the updated sudoku matrix
             (enough to find solutions for simple sudokus)
   method 2: tests various solutions by guessing an answer for a
             single cell (calls method 1)
             (enough for more complicated sudokus)
   method 3: tests various solutions by guessing answers for two cells
             (calls method 2).
             (works excellent for the most difficult sudokus)
4. prints results to the screen including
   information what method has succeeded.

Alex