#include <stdlib.h>

include <stdio.h>
static void swap(void x, void y, size_t l) {
   char a = x, b = y, c;
   while(l--) {
      c = a;
      a++ = b;
      b++ = c;
   }
}
static void sort(char array, size_t size, int (cmp)(void,void), int begin, int end) {
   if (end > begin) {
      void *pivot = array + begin;
      int l = begin + size;
      int r = end;
      while(l < r) {
         if (cmp(array+l,pivot) <= 0) {
            l += size;
         } else {
            r -= size;
            swap(array+l, array+r, size);
         }
      }
      l -= size;
      swap(array+begin, array+l, size);
      sort(array, size, cmp, begin, l);
      sort(array, size, cmp, r, end);
   }
}
void qsort(void array, size_t nitems, size_t size, int (cmp)(void,void)) {
   sort(array, size, cmp, 0, (nitems-1)*size);
}
typedef int type;
int type_cmp(void a, void b){ return ((type)a)-((type)b); }
main(){ / simple test case for type=int /
  int num_list[]={5,4,3,2,1};
  int len=sizeof(num_list)/sizeof(type);
  char *sep="";
  int i;
  qsort(num_list,len,sizeof(type),type_cmp);
  printf("sorted_num_list={");
  for(i=0; i<len; i++){
    printf("%s%d",sep,num_list[i]);
    sep=", ";
  }
  printf("};\n");
}
</pre>