A C program to solve sudokus.

1. Compile the sudoku.cpp file using any compilers supporting C 11
2. Run the executable file, a Terminal (or cmd on Windows system) window popped up
3. Enter the sudoku puzzle in the Terminal (or cmd) window in the following format:
   • The sudoku puzzle should be 9 * 9
   • For each positon, enter the number (1-9) in the position; if there is nothing in the position, enter 0
   • There could be space(s), line break(s), other character(s) or nothing between the numbers
4. The answer should be given now