Binary search in c++
//By Sudhanshu Sharan
#include<iostream>
#include<cmath>
using namespace std;
// BCT= o(1) and WCT=O(logn) time taken for unsucessful search is always o(logn)
int BinSearch( int arr[],int key,int len)
{
int h,mid,l;
l=0;
h=len-1;
while(l<=h)
{
mid=((l+h)/2);
if(key==arr[mid])
return mid;
else if(key<arr[mid])
h=mid-1;
else
l=mid+1;
}
return -1;
}
int main()
{
int key,i,len;
int arr[] = {1,2,3,6,9,12,15,34,54};
len=sizeof(arr)/sizeof(arr[0]);
cout<<"enter the key to be searched";
cin>>key;
int result= BinSearch(arr,key,len);
(result == -1)
? cout<<"Element is not present in the array"<<endl
: cout<<"Element is present at index : "<<result<<endl;
for(i=0;i<len-1;i++)
cout<<arr[i]<<" ";
return 0;
}