快速排序以及二分查找的实现

#include <stdio.h>

int BinSearch(int a[],int left,int right,int key);//声明二分查找
void QuickSort(int a[],int left,int right);//声明快速排序

int main()
{
int a[101];
int i,n,key;
printf("Please input total number:");
scanf("%d",&n);
printf("Now please input %d numbers:",n);
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
QuickSort(a,0,n-1);
printf("The array after QuickSort is :\n");
for(i=0;i<n;i++)
{
printf("%d ",a[i]);
}
printf("\nPlaese input the number you want to search:");
scanf("%d",&key);
int order=BinSearch(a,0,n-1,key);
if(order==-1)
{
printf("Can not find number %d\n",key);
}
else
{
printf("The order of number %d is %d\n",key,order+1);
}
return 0;

}

void QuickSort(int a[],int left,int right)
{
int i=left,j=right;
int key=a[left];
if(left>right)
return;
while(i<j)
{
while(a[j]>=key&&i<j)
j--;
a[i]=a[j];
while(a[i]<=key&&i<j)
i++;
a[j]=a[i];
}
a[i]=key;
QuickSort(a,left,i-1);
QuickSort(a,i+1,right);
}

int BinSearch(int a[],int left,int right,int key)
{
int low=left,high=right,mid;
if(left<=right)
{
mid=low+(high-low)/2;
if(a[mid]==key)
{
return mid;
}
if(a[mid]>key)
{
return (BinSearch(a,low,mid-1,key));
}
else
{
return (BinSearch(a,mid+1,high,key));
}
}
return -1;
}