#include<bits/stdc++.h>
using namespace std;

/*
int binarySearch(int a[],int key,int start,int end){
    int mid = start + (end-start)/2;
    if(a[mid]==key) return mid;
    else if(a[mid]>key) return binarySearch(a,key,start,mid-1);
    else return binarySearch(a,key,mid+1,end);
}
*/

int binarySearch(int a[],int key,int start,int end){
    int mid = start + (end-start)/2;
    if(a[mid]==key) return mid;
    else if(a[mid]>key) binarySearch(a,key,start,mid-1);
    else binarySearch(a,key,mid+1,end);
}


int main(){
    int a[9]={1,2,3,4,5,6,7,8,9};
    cout<<binarySearch(a,8,0,7)<<"\n";
    cout<<binarySearch(a,3,0,7)<<"\n";
    return 0;
}