void qsort(void * base,size_t nmemb,size_t size ,int(*compar)(const void *,const void *));

#include<stdio.h> 
#include<stdlib.h> 
#include<math.h> 
#include<string.h> 
 
void main(void) 
{ 
  int i; 
  int a[10]={0,1,2,3,4,5,6,7,8,9}; 
  char b[10]={'a','b','c','d','e','f','g','h','i','j'}; 
  double c[10]={0.1,0.2,0.9,0.5,0.3,0.6,0.7,0.8,1.1,1.2}; 
  int cmp1(const void * a,const void * b) 
  { 
    return (*(int*)a-*(int*)b);//a>b 返回正值 
  } 
 
  int cmp2(const void * a,const void *b) 
  { 
    return(*(char*)a-*(char*)b); 
  } 
  int cmp3(const void * a,const void * b) 
  { 
    if(fabs(*(double*)a-*(double *)b)<1*exp(-20)) 
      return 0; 
    else 
      return(((*(double*)a-*(double*)b)>0)?1:-1); 
  } 
 
  qsort(a,10,sizeof(int),&cmp1);//對(duì)于函數(shù)指針（指向函數(shù)的指針），直接傳入函數(shù)名和函數(shù)名進(jìn)行& 
                 //運(yùn)算都是可以的，因?yàn)樵谡{(diào)用函數(shù)時(shí)也是取的函數(shù)的地址 
  qsort(b,10,sizeof(char),cmp2); 
  qsort(c,10,sizeof(double),cmp3); 
  for(i=0;i<10;i++) 
    printf("%d ",a[i]); 
  for(i=0;i<10;i++) 
    printf("%c ",b[i]); 
  for(i=0;i<10;i++) 
    printf("%lf ",c[i]); 
}