1. Press the green flag to start. 2. Click on a square to select it. 3. Press a number key (1-9) to place that number in the selected square. 4. When you're ready to solve the puzzle, press the green 'solve' button. 5. The solution will be displayed. 6. Press the red 'clear' button to clear all the squares and start over.
This project uses an approach that I use when I solve Sudoku by hand. First it eliminates possibilities for each empty square, based on the squares that are filled in. Whenever a new square is filled in, it eliminates more possibilities in other squares.
