快速查找得出索引位置

#include<iostream>
using namespace std;

int Find(int ar[],int low,int high,int key)
{
 if(low>high)
  return -1;
 int mid = (low+high)/2;
 if(ar[mid] == key)
  return mid;
 else if(key<ar[mid])
  return Find(ar,low,mid-1,key);
 else
  return Find(ar,mid+1,high,key);
}
void main()
{
 int ar[]={1,23,45,67,90,123,456,678,900,1000};
 int key;
 cout<<"intput key:";
 cin>>key;
 int n = sizeof(ar) / sizeof(int);
 int low = 0;
 int high = n-1;
 int index=Find(ar,low,high,key);
 cout<<"index ="<<index<<endl;
}