（算法设计技巧与分析）BinarySearchrec

#include<iostream>using namespace std;int binarysearch(int a[],int low,int high,int x);int main(){int a[11],x,result;for(int i=0;i<11;i++){a[i]=i*2;cout<<a[i]<<" ";}cout<<endl;cin>>x;result=binarysearch(a,0,10,x);if(result==-1)cout<<"no find!"<<endl;else cout<<"a["<<result<<"]="<<a[result]<<endl;return 0;}int binarysearch(int a[],int low,int high,int x){if(low>high)return -1;else{int mid=(low+high)/2;if(a[mid]==x)return mid;else if(a[mid]>x)return binarysearch(a,low,mid-1,x);else return binarysearch(a,mid+1,high,x);}}