binary search.cpp

#include<iostream>
using namespace std;
int binarySearch(int* arr,int n,int x){
 int s=0,e=n-1;
  while(s<=e){
   int mid=(s+e)/2;
    if(arr[mid]==x)
      return mid;
    else if(arr[mid]<x)
      e=mid+1;
    else
      s=mid-1;
  }
  return -1;
}
int main(){
  int n;
  cin>>n;
  int* arr=new int[n];
  for(int i=0;i<n;i++){
   cin>>arr[i]; 
  }
  int x;
  cin>>x;
  cout<<binarySearch(arr,n,x)<<endl;
}