Array-strings sorted using qSort in C

Question

the question is simple: there is some way that the ordered array that returns me the "qsort", is returned in reverse, ie I want to avoid the use of any auxiliary array to invest the resulting array using qsort.

this is my code, which reads from standard input strings to be sorted, and uses a comparison function for sorting.

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <stdio.h>
    #include <string.h>

            int cstring_cmp(const void *a, const void *b)
            {
                const char **ia = (const char **)a;
                const char **ib = (const char **)b;
                return strcasecmp(*ia, *ib);
                /* strcmp functions works exactly as expected from
                comparison function */
            }

Thanks in advance for your response, sorry for my English

            int main (int argc, char *argv [])

            {
            int number;
            char temp [4000];

            printf("input number: ");
            scanf("%d",&number);

            char* array_string [number];
            int i;
            for (i=0;i<number;i++) {
            scanf(" %[^\n]", temp);
            array_string [i] = (char*)malloc((strlen(temp)+1)*sizeof(char));
            strcpy(array_string[i], temp);
            }


            size_t large = sizeof(array_string) / sizeof(char *);
            qsort(array_string,large ,sizeof(char *) ,cstring_cmp );
            printf ("\n");
            printf ("the sorted array list is:\n");
            for (i=0;i<large;i++)
            printf("%s\n", array_string [i]);
                    return 0;
            }

return -1 * strcasecmp(*ia, *ib); might work. If you reverse the comparison function the array will be reversed. — Ronny Brendel
– Ronny Brendel, Commented Oct 31, 2010 at 0:02

Blastfurnace · Accepted Answer · 2010-10-31 00:06:49Z

4

Have you just tried reversing the order of parameters to strcasecmp?

return strcasecmp(*ib, *ia);

answered Oct 31, 2010 at 0:06

Blastfurnace

18.7k57 gold badges61 silver badges73 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

xscott · Accepted Answer · 2010-10-31 00:02:30Z

3

Does this do what you want?

        int cstring_cmp(const void *a, const void *b)
        {
            const char **ia = (const char **)a;
            const char **ib = (const char **)b;
            return -strcasecmp(*ia, *ib);
            /* return the negative of the normal comparison */
        }

answered Oct 31, 2010 at 0:02

xscott

2,43018 silver badges18 bronze badges

Collectives™ on Stack Overflow

Array-strings sorted using qSort in C

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related