BINARY SEARCH

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

int binary_search(int*a,int n,int k)
{
    int high=n-1, low=0;
    
    while(high>=low)
    {
    
    int mid= low+ (high-low)/2;
    
       if(a[mid]==k)
       {  
          return mid;
       }
       else if(k<a[mid])
       high=mid-1;
       else
       low=mid+1;
      }
      
      
      return -1;



}



int main() {
	int a[5]={1,2,3,4,5};
	cout<<binary_search(a,5,4)<<endl;
	return 0;
}