How to use qsort for an array of strings?

Question

#include 
#include 
#include 

int sortstring(const void *str1, const void *str2) {
    const char *rec1 = str1;
    c         


        

Answer 1

Your comparator is being sent each pair by-address. I.e. they're pointer-to-pointer-to-char.

Change the comparator to:

int sortstring( const void *str1, const void *str2 )
{
    char *const *pp1 = str1;
    char *const *pp2 = str2;
    return strcmp(*pp1, *pp2);
}

Likewise, your sortutil needs to know the number of items being sorted, as well as pass the correct size of each item. Change that to:

void sortutil(char* lines[], int count)
{
    qsort(lines, count, sizeof(*lines), sortstring);
}

Finally, the call from main() should look like this:

sortutil(arr, numlines);

That should do it.