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

What the compar function gets are pointers to the elements in your array, which in this case, are pointers to char. So the parameters str1 and str2 are actually pointers to pointers to char. You must cast them like this:

int sortstring( const void *str1, const void *str2 )
{
    const char *rec1 = *(char**)str1;
    const char *rec2 = *(char**)str2;
    int val = strcmp(rec1, rec2);

    return val;
}

Then you have to use the proper element size in qsort.

qsort(lines, 200, sizeof(char*), sortstring);