Sudoku is a FLTK-based version of the game of Sudoku.
Sudoku (pronounced soo-dough-coo with the emphasis on the first
syllable) is a simple number-based puzzle/game played on a 9x9
grid that is divided into 3x3 subgrids. The goal is to enter a
number from 1 to 9 in each cell so that each number appears only
once in each column and row.
At the start of a new game, Sudoku fills in a random selection of
cells for you - the number of cells depends on the difficulty
level you use. Click in any of the empty cells or use the arrow
keys to highlight individual cells and press a number from 1 to 9
to fill in the cell. To clear a cell, press 0, Delete, or
Backspace. As you complete each subgrid, correct subgrids are
highlighted in green. When you have successfully completed all
subgrids, the entire puzzle is highlighted until you start a new
As you work to complete the puzzle, you can display possible
solutions inside each cell by holding the Shift key and pressing
each number in turn. Repeat the process to remove individual
numbers, or press a number without the Shift key to replace them
with the actual number to use.