C语言实现快速排序算法

C语言实现快速排序算法

#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");  
}