fn print_board(board: &[usize; 81]) {
    println!();
    for (i, num) in board.iter().enumerate() {
        print!(" {}", if num == &0 { "_".to_string() } else { num.to_string() });
        if (i %  3) ==  2 { print!(" "); }
        if (i %  9) ==  8 { println!();  }
        if (i % 27) == 26 { println!();  }
    }
}
/// prints the current state of the board
prints the current state of the board
prints the current state of the board
fn print_board(board: &[usize; 81]) {
    println!();
    for (i, num) in board.iter().enumerate() {
        print!(" {}", if num == &0 { "_".to_string() } else { num.to_string() });
        if (i %  3) ==  2 { print!(" "); }
        if (i %  9) ==  8 { println!();  }
        if (i % 27) == 26 { println!();  }
    }
}
fn print_board ( board : & [ usize ; 81 ] ) { println ! ( ) ; for ( i , num ) in board . iter ( ) . enumerate ( ) { print ! ( " " if num 0 { " " to_string ( ) } else { num to_string ( ) } ) ; if ( i % 3 ) == 2 { print ! ( " " ) ; } if ( i % 9 ) == 8 { println ! ( ) ; } if ( i % 27 ) == 26 { println ! ( ) ; } } }
prints the current state of the board
prints the current state of the board
board
&[usize; 81]
board
&[usize; 81]