Quick Sort : Array of pointers to structures

Write a program in C for Quick Sort
 

#include "stdio.h"

#include "string.h"

#include "stdlib.h"

struct node

{

            char *str;

};

/* compare function for qsort */

static int cmpr(const void *a, const void *b);

int main(void)

{

            struct node **strarray = NULL;

            int i = 0, count = 0;

            char line[1024];

            while(fgets(line, 1024, stdin) != NULL)

            {

                        /* add ONE element to the array */

                        strarray = (struct node **)realloc(strarray, (count + 1) * sizeof(struct node *));

                        /* allocate memory for ONE `struct node` */

                        strarray[count] = (struct node *)malloc(sizeof(struct node));

                        /* copy the data into the new element (structure) */

                        strarray[count]->str = strdup(line);

                        count++;

            }

            /* before sorting ... */

            printf("Before:\n");

            for(i = 0; i < count; i++)

            {

                        printf("[%d]->str: %s", i, strarray[i]->str);

            }

            /* qsort array of structures */

            qsort(strarray, count, sizeof(*strarray), cmpr);

           

            /* after sorting ... */

            printf("\n--\nAfter:\n");

            for(i = 0; i < count; i++)

            {

                        printf("[%d]->str: %s", i, strarray[i]->str);

            }

           

            /* free all strarray elements */

            for(i = 0; i < count; i++)

            {

                        free(strarray[i]->str);

                        free(strarray[i]);

                        i++;

            }

            free(strarray);

           

            return 0;

}

/* compare function for qsort */

static int cmpr(const void *a, const void *b)

{

            struct node * const *one = a;

            struct node * const *two = b;

            return strcmp((*one)->str, (*two)->str);

}