How do I sort a linked list of structures by one of the fields?

Question

Wow now i know I dont. Lol.

I\'ve got my structure like this:

struct Medico{ 
int Id_Doctor;
int Estado;
char Nombre[60]; ////focus on this part of t         


        

Answer 1

Implementing a mergesort over a linked list in C is quite easy:

#include 
#include 
#include 

struct node {
    struct node *next;
    char *data;
};

struct node *
divlist (struct node *n) {
    int i = 0;
    if (n) {
        struct node *tail, *n2 = n;
        while (1) {
            n2 = n2->next;
            if (!n2) break;
            if (i++ & 1) n = n->next;
        }
        tail = n->next;
        n->next = NULL;
        return tail;
    }
    return NULL;
}

struct node *
mergelists(struct node *a, struct node *b) {
    struct node *n;
    struct node **last = &n;
    if (!a) return b;
    if (!b) return a;

    while (1) {
        if (strcmp(a->data, b->data) > 1) {
            *last = b;
            last = &b->next;
            b = b->next;
            if (!b) {
                *last = a;
                break;
            }
        }
        else {
            *last = a;
            last = &a->next;
            a = a->next;
            if (!a) {
                *last = b;
                break;
            }
        }
    }
    return n;
}

struct node *
sortlist (struct node *n) {
    struct node *tail = divlist(n);
    if (!tail) return n;
    return mergelists(sortlist(n), sortlist(tail));
}

int main(int argc, char *argv[]) {
    int i;
    struct node *n1, *n = NULL;
    for (i = argc; --i >= 1;) {
        n1 = (struct node *)malloc(sizeof(*n1));
        n1->data = argv[i];
        n1->next = n;
        n = n1;
    }

    n1 = n = sortlist(n);

    while (n1) {
        printf("%s\n", n1->data);
        n1 = n1->next;
    }
    return 0;
}

Note that you will have to modify this code to use your data structure and the right comparison!