快排序（递归算法）

#include<stdio.h>

#include<math.h>

#define N 10

void quicksort(int a[],int low,int high);

int split(int a[],int low,int high);

main()

{

  int a[N],i;

  printf("Enter %d numbers to be sorted: ",N);

  for(i=0;i<N;i++)

  {

    scanf("%d",&a[i]);

  }

  quicksort(a,0,N-1);

  printf("In sorted order: ");

  for(i=0;i<N;i++)

  {

    printf("%d  ",a[i]);



  }

  printf("\n");

  getch();

}

void quicksort(int a[],int low,int high)

{

   int middle;

   if(low>=high)return;

   middle=split(a,low,high);

   quicksort(a,low,middle-1);

   quicksort(a,middle+1,high);

 }

int split(int a[],int low,int high)

{

   int part_element=a[low];

   for(;;){

   while(low<high&&part_element<=a[high])

     high--;

   if(low>=high) break;

   a[low++]=a[high];



   while(low<high&&a[low]<=part_element)

     low++;

   if(low>=high) break;

   a[high--]=a[low];

   }

   a[high]=part_element;

   return high;

}