Finding difference between adjacent integers in an array - recursive Implementation
In situations like this, it is much simpler to handle the corner case outside the recursive call:

    differenceSequence(int array[], int size, int resultArray[])
    {
        if (size == 0) {
            do_corner_case();
            return;
        }
        differenceSequenceRecursive(array, size, resultArray);
    }


and the helper differenceSequenceRecursive function only deals with regular case.