How to compare C++ string using qsort in c?

Question

I tried to learn the qsort function of the c-library stdlib. This is provided even in c++. But i dont understand how to use them for sorting

Answer 1

Better be C++ oriented and use std::sort for your array:

#include 
#include 
#include 
#include 

int main() {

   std::string obj[4] = {"fine", "ppoq", "tri", "get"};
   std::sort(obj, obj + 4);
   std::copy(obj, obj + 4, std::ostream_iterator(std::cout, "\n"));
}

AFAIK - std::sort uses quick sort.

[UPDATE] See comments, std::sort is not always pure quick sort.

[UPDATE2]

If you want to learn qsort - change std::string to const char* and define function based on strcmp. Remember that qsort passes pointers to elements in an array - so dereference const void* to get const char*. See:

#include 
#include 

int compare_cstr(const void* c1, const void* c2) 
{ 
   return strcmp(*(const char**)(c1), *(const char**)(c2)); 
}

int main() {

   const char* obj[4] = {"fine", "ppoq", "tri", "get"};
   qsort(obj, 4, sizeof(obj[0]), compare_cstr);
   std::copy(obj, obj + 4, std::ostream_iterator(std::cout, "\n"));
}