Binary Search

//array must be sorted

bool b_search(int arr[],int strt,int lst,int target) //strt=starting index, lst=last index
{
    int lo=strt,hi=lst;

    while(lo<=hi)
    {
        int mid=lo+(hi-lo)/2;

        if(arr[mid]==target)
            return true;
        else if(arr[mid]<target)
            lo=mid+1;
        else
            hi=mid-1;
    }

    return false;
}