To do this we can use the rand() function in C++. Afterwards, we randomly select indices from all possible indices and display those to the player. We can store the number of hints we want the players to have or take as input the difficulty of puzzle the player wants and set number of hints accordingly.
Hints: As we all know, sudoku puzzle initinally gives the player some hints which they can use to solve the puzzle. We can store 10s and 100s of solved puzzles to generate a very high number of combinations. The second method is better for small to medium-scale applications. There are many ways to generate a Sudoku puzzle, 2 of the most popular ways are either to start from scratch and use recursive backtracking to generate sudoku or use a solved sudoku puzzle and make combinations of different Sudokus by swapping digits, swapping columns of 3x3 blocks and swapping rows of 3x3 blocks.
To color the grid we can use SetConsoleTextAttribute() function in Windows.h header file to change the color of output in console and then use 'for' loops to print the values in Sudoku. The 9x9 Sudoku Grid should be visually pleasing and the blocks should be easy to separate out, so the player can easily spot the different regions in the Sudoku grid.