int i = 5;
struct node *tmp, *tmp2, *a, *b, *c, *d;

b = c = tmp  = NULL;
d = tmp2 = a = NULL;

for(i = 0; i < 4; i++)
{
    if(tmp == NULL)
    {
        tmp2 = tmp = create();
        tmp -> value = i;
        tmp -> next = create();
        tmp -> next -> value = i + 4;
        a = tmp2 -> next;
        tmp = tmp -> next;
    }
    else
    {
        tmp -> next = create();
        tmp -> value = i;
        tmp -> next -> value = i + 4;
        
        if(i == 1)
            b = tmp -> next;
        else if(i == 2)
            c = tmp -> next;
        else
            d = tmp -> next;
        
        tmp = tmp -> next;
    }
}

tmp -> next = tmp2;
tmp -> value = i;
tmp = tmp -> next -> next -> next;