#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

struct sll_node
{
    int data ;
    struct sll_node * next ;
};
bool insert_before ( struct sll_node ** node, int data )
{
    struct sll_node * new_node = ( struct sll_node *)
                                 malloc ( sizeof ( struct sll_node ));
    if ( NULL != new_node )
    {
        new_node -> data = data ;
        new_node -> next = * node ;
        *node = new_node ;
        return true ;
    }
    return false ;
}
bool insert_back ( struct sll_node ** node, int data )
{
    *node = ( struct sll_node *) malloc ( sizeof ( struct sll_node ));
    if ( NULL != * node )
    {
        (*node )->data = data ;
        (*node )->next = NULL ;
        return true ;
    }
    return false ;
}
bool insert_node ( struct sll_node ** node, int data )
{
    if ( NULL != * node )
    {
        if ((* node ) ->data <= data )
            return insert_before (node, data );
        else
            return insert_node (&(* node ) ->next, data );
    }
    else
        return insert_back (node, data );
}
void delete_node ( struct sll_node ** node, int data )
{
    if ( NULL != * node )
    {
        if ((* node ) ->data == data )
        {
            struct sll_node * next = (* node ) ->next ;
            free (* node );
            * node = next ;
        }
        else
            delete_node (&(* node ) ->next, data );
    }
}


void print_list ( struct sll_node * node )
{
    if ( NULL != node )
    {
        printf ("%d ", node -> data );
        print_list (node -> next );
    }
    else
        printf ("\n");
}
void print_list_backwards ( struct sll_node * node )
{
    if ( NULL != node )
    {
        print_list_backwards (node -> next );
        printf ("%d ", node -> data );
    }
}
void remove_list ( struct sll_node ** node )
{
    if ( NULL != * node )
    {
        remove_list (&(* node ) ->next );
        free (* node );
    }
}

int evaluate_operation ( struct sll_node *node, int (* operation ) (int result, struct sll_node * node ) )
{
    if (( NULL != node ) && ( NULL != operation ) )
        return operation ( evaluate_operation (node ->next, operation ),node ) ;

    return 0;
}

int iterate_list(struct sll_node *list_pointer,int (*action)(int result, struct sll_node *list_pointer))
{
    int result=1;
    for(; list_pointer; list_pointer=list_pointer->next)
        if(action)
        result=action(result,list_pointer);
    return result;
}

int parzyste(int result, struct sll_node *list_pointer)
{
    if((list_pointer->data)%2 == 0)
        result*=list_pointer->data;
    return result;
}

int nieparzyste(int result, struct sll_node *list_pointer)
{
    if((list_pointer->data)%2 != 0)
        result*=list_pointer->data;
    return result;
}




int main ()
{
    struct sll_node * front = NULL ;
    int i;
    for (i=1; i <5; i++)
        if (! insert_node (& front, i))
            fprintf (stderr, " Error while inserting %d!\n", i);
    for (i=6; i <10; i++)
        if (! insert_node (& front, i))
            fprintf (stderr, " Error while inserting %d!\n", i);
    printf (" List elements :\n");
    print_list ( front );
    if (! insert_node (& front, 0))
        fprintf (stderr, " Error while inserting 0!\n");
    printf (" List elements after insertion of 0:\n");
    print_list ( front );
    if (! insert_node (& front, 5))
        fprintf (stderr, " Error while inserting 5!\n");
    printf (" List elements after insertion of 5:\n");
    print_list ( front );
    if (! insert_node (& front, 7))
        fprintf (stderr, " Error while inserting 7!\n");
    printf (" List elements after insertion of 7:\n");
    print_list ( front );
    if (! insert_node (& front, 10) )
        fprintf (stderr, " Error while inserting 10!\n");
    printf (" List elements after insertion of 10:\n");
    print_list ( front );

    printf("Iloczyn elementow parzystych:\n");
    printf("%d",iterate_list(front,parzyste));
    printf("\nIloczyn elementow nieparzystych\n");
    printf("%d",iterate_list(front,nieparzyste));

    printf ("\nList elements printed backwards :\n");
    print_list_backwards ( front );
    printf ("\n");
    delete_node (& front, 0);
    printf (" List elements after deletion of 0:\n");
    print_list ( front );
    delete_node (& front, 1);
    printf (" List elements after deletion of 1:\n");
    print_list ( front );
    delete_node (& front, 1);
    printf (" List elements after deletion of 1:\n");
    print_list ( front );
    delete_node (& front, 4);
    printf (" List elements after deletion of 4:\n");
    print_list ( front );
    delete_node (& front, 7);
    printf (" List elements after deletion of 7:\n");
    print_list ( front );
    delete_node (& front, 10);
    printf (" List elements after deletion of 10:\n");
    print_list ( front );
    remove_list (& front );
    front = NULL ;
    return 0;
}