sudoku in c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   sudoku.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: jiwok <[email protected]>                       +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/07/20 20:00:06 by jiwok             #+#    #+#             */
/*   Updated: 2019/07/20 21:18:15 by jiwok            ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include <stdlib.h>
#include <unistd.h>

void    ft_print_sudoku(int **arr)
{
    int i;
    int j;

    i = 0;
    while (i < 9)
    {
        j = 0;
        while (j < 9)
        {
            write(1, &arr[i][j], 1);
			if (j != 8)
            	write(1, " ", 1);
            j += 1;
        }
        write(1, "\n", 1);
        i += 1;
    }
}

int		ft_used_in_box(int **arr, int startrow, int startcolumn, int nb)
{
	int i;
	int j;

	startrow = startrow - (startrow % 3);
	startcolumn = startcolumn - (startcolumn % 3);
	i = 0;
	while (i < 3)
	{
		j = 0;
		while (j < 3)
		{
			if (arr[i + startrow][j + startcolumn] == (nb + 48))
				return (1);
			j += 1;
		}
		i += 1;
	}
	return (0);
}

int		ft_safe(int **arr, int row, int column, int nb)
{
    int i;

    i = 0;
    while (i < 9)
    {
        if ((arr[row][i] > 48 && arr[row][i] <= 57 && arr[row][i] == (nb + 48)) ||
            (arr[i][column] > 48 && arr[i][column] <= 57 && arr[i][column] == (nb + 48)) ||
			ft_used_in_box(arr, row, column, nb) == 1)
            return (0);
        i += 1;
    }
    return (1);
}

int     ft_solvesudoku(int **arr)
{
    int i;
    int j;
    int k;

	i = 0;
	while (i < 9)
	{
		j = 0;
		while (j < 9)
		{
            if (arr[i][j] < 49 || arr[i][j] > 57)
            {
                k = 1;
                while (k <= 9)
                {
                    if (ft_safe(arr, i, j, k))
                    {
                        arr[i][j] = k + 48;
                        
                        if (ft_solvesudoku(arr) == 1)
                            return (1);
                        arr[i][j] = 48;
                    } 
                    k += 1;
                }
                return (0);
            }
            else
                j += 1;
		}
        i += 1;	
	}
    return (1);
}

void    ft_assign_elements(int **arr, char **argv)
{
    int i;
    int j;

    i = 0;
    while (i < 9)
    {
        j = 0;
        while (j < 9)
        {
            if (argv[i + 1][j] > 48 && argv[i + 1][j] <= 57)
                arr[i][j] = argv[i + 1][j];
            j += 1;
        }
        arr[i][j] = '\0';
        i += 1;
    }
}

int     **ft_allocate_memory()
{
    int **arr;
    int i;

    arr = (int **)malloc(sizeof(int *) * 10);
    i = 0;
    while (i < 9)
    {
        arr[i] = (int *)malloc(sizeof(int) * 10);
        i += 1;
    }
    arr[i] = 0;
    return arr;
}

int		main(int argc, char **argv)
{
    int **arr;

    if (argc == 10)
    {
        arr = ft_allocate_memory();
        ft_assign_elements(arr, argv);
        if (ft_solvesudoku(arr) == 1)
            ft_print_sudoku(arr);
        else
            write(1, "Error\n", 6);
    }
    return (0);    
}