Thread: sort linked list using quick sort in C

hi I am trying to sort a linked list using quick sort in C. Here is my code--Actually, first I am inserting data in the list from a file. For a small file, it's working fine. But for large file it's just not working. Please help me out with this. What I need to add??Thanks

Code:

struct node
{
    int data;
    struct node *link;
    struct node *plink;
};
struct node *first=NULL, *last=NULL;
void swap(struct node* a,struct node* b)
{
    int temp;
    temp=a->data;
    a->data=b->data;
    b->data=temp;
}

void qsort(struct node *low, struct node *high)
{
    if(low==NULL || high==NULL || low == high || low->plink == high)
    return ;

    struct node *pivot=low, *tmp=low->link;
    while(tmp != high->link)
    {
            if(tmp->data < low->data)
            {
                    swap(pivot->link, tmp);
                    pivot = pivot->link;
            }
            tmp = tmp->link;
    }
    swap(low, pivot);
    qsort(low, pivot->plink);
    qsort(pivot->link, high);
}

You should avoid calling your function qsort as there is a standard C function with that name. Try quicksort instead.

Also, posting enough code for us to compile, run and test your algorithm, and the large input file for which it fails, would be very beneficial. I really don't want to write a main function and linked list insert function for your program.