C#

using System;
using System.Collections.Generic;
using System.Text;

namespace sudoku
{
    class sudoku
    {
        private int[] values_right = new int[81];

        private int[] squareindex = new int[81] {0, 0, 0, 1, 1, 1, 2, 2, 2,
                                                 0, 0, 0, 1, 1, 1, 2, 2, 2,
                                                 0, 0, 0, 1, 1, 1, 2, 2, 2,
                                                 3, 3, 3, 4, 4, 4, 5, 5, 5,
                                                 3, 3, 3, 4, 4, 4, 5, 5, 5, 
                                                 3, 3, 3, 4, 4, 4, 5, 5, 5, 
                                                 6, 6, 6, 7, 7, 7, 8, 8, 8, 
                                                 6, 6, 6, 7, 7, 7, 8, 8, 8, 
                                                 6, 6, 6, 7, 7, 7, 8, 8, 8};

        private int[] posible_values = new int[9] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        public sudoku()
        {
            this.generate();
        }

        public void generate()
        {
            /*
            int[] values = {8, 4, 6, 3, 5, 1, 7, 9, 2, 
                            5, 1, 3, 9, 2, 7, 4, 6, 8, 
                            7, 9, 2, 6, 8, 4, 1, 3, 5,
                            4, 3, 8, 5, 7, 9, 6, 2, 1, 
                            1, 7, 9, 2, 4, 6, 5, 8, 3, 
                            2, 6, 5, 8, 1, 3, 9, 7, 4, 
                            6, 8, 1, 7, 3, 5, 2, 4, 9, 
                            9, 2, 4, 1, 6, 8, 3, 5, 7, 
                            3, 5, 7, 4, 9, 2, 8, 1, 6};
            */


            Random rnd = new Random();
            int i;
           


            for (i = 0; i < 81; i++)
            {
                while (this.values_right[i] == 0)
                    this.values_right[i] = rnd.Next(1, 90) % 10;


                while (check_position(i) == 0)
                {
                    this.values_right[i] = (this.values_right[i] + 1) % 10;

                }
            }

        }

        public int[] get_values_right()
        {
            return values_right;
        }

        int check_position(int i)
        {
            if (this.values_right[i] == 0)
                return 0;

            Random rnd = new Random();
            int row = i - (i % 9);
            int col = i % 9;
            int position;

             for (position = row; position < row + 9; position++)
            {
                if (position == i)
                    continue;

                if (this.values_right[position] == this.values_right[i])
                    return 0;
            }

           /*for (position = col; position < 80; position += 9)
            {
                if (position == i)
                    continue;

                if (this.values_right[position] == this.values_right[i])
                    return 0;
            }*/


            return 1;
        }
    }
}