binsearch

int BinarySearch (int* array, int key, int arraylenght) //id probably pass this function the max too
{                                               //Note that this only works for sorted arrays, 
                                                //so you need to input your values in rising order, 
                                                //hopefully not a problem.
    int start = 0;
    int end = max - 1;
    int mid;
    int prev=-1; //This is our addition to the binary search, -1 is assumed to be an invalid value
    while (true) //don't do this when you program a car break-system
    {
        mid = (start + end) / 2;
        
        if (key == a[mid]) //we found the exact value we wanted, return
            return mid;
        if (prev==mid) //we found that this is the same value we compared to last time, return
        {
            return mid;
        }
        else if (key < a[mid])
        {
            end = mid - 1;
        }
        else 
        {
            start = mid + 1;
        }
        prev=mid;
    }
    return -1; //The compiler wants to be sure we always return values, so we need to put this here, this will never execute
}