A picture is worth… 1.500 words

Simple recursion explanation

Here´s an example with some code…

float _pow_recursion(float x, float y)
{
    if (y == 0)
        return (1);
    if (y < 0)
        return (_pow_recursion(x, y + 1) / x);

    return (_pow_recursion(x, y - 1) * x);
}