#include<bits/stdc++.c>

int binarysearch(int arr[], int l, int r, int x){
  if(r>=l){
     int mid= l+(r-1)/2;
     if(arr[mid]== x){
       return mid;
     }
    if(x<arr[mid]){
      return binarysearch(arr, l ,mid-1, x);
    }
    if(x>arr[mid]){
      return binarysearch(arr, mid+1, r, x);
    }
  }
  return -1;
  
}

int main(){
  int arr[]= {10, 20, 30, 40, 50};
  int x= 30;
  int n= sizeof(arr)/ sizeof(arr[0]);
  int result= binarysearch(arr, 0, 1, n-1m, x);
  (result==-1)? cout<<"Element is not present" : cout<<"Element is present at"<<result;
  return 0;
  
}