Search an element in a sorted and rotated array in C.

searchRotated.c

int get_pivot(int * arr, int arr_size) {
    int index = 1;
    while(index < arr_size && arr[index] > arr[index - 1]) {
        index++;
    }

    if (index >= arr_size) 
        return -1;
    return index;
}

int binary_search(int x, int * arr, int start, int end) {
    if (start > end)
        return -1;
    int middle = (start + end) / 2;
    if (arr[middle] == x)
        return middle;
    else if (x > arr[middle])
        return binary_search(x, arr, middle + 1, end);
    return binary_search(x, arr, start, middle - 1);
}

int find_x(int x, int * arr, int arr_size) {
    int pivot = get_pivot(arr, arr_size);
    if (pivot == -1)
        return binary_search(x, arr, 0, arr_size - 1);

    if (arr[0] < x)
        return binary_search(x, arr, 1, pivot - 1);
    return binary_search(x, arr, pivot, arr_size - 1);
}