This is a simple command-line Sudoku solver written in C for mere educational

purposes. It expects a partially solved Sudoku board as input, that will be

read from standard input or the file given as the first program argument, if

given. Then, it will try to solve the board and print it solved on standard

output.

The input format is simple. The board must be given as cells from top to bottom

and left to right, with empty cells represented by dots and other cells

represented by its value. Example:

5 3 . . 7 . . . .

6 . . 1 9 5 . . .

. 9 8 . . . . 6 .

8 . . . 6 . . . 3

4 . . 8 . 3 . . 1

7 . . . 2 . . . 6

. 6 . . . . 2 8 .

. . . 4 1 9 . . 5

. . . . 8 . . 7 9

Same example in a more compact format, also valid:

53..7....

6..195...

.98....6.

8...6...3

4..8.3..1

7...2...6

.6....28.

...419..5

....8..79