Compute base raised to exponent recursively – no loop. exponent is always 0 or greater.
This is the lesson’s factorial pattern with the multiplication changed: the base case is exponent == 0 (raising
anything to the power 0 is 1), and the recursive case multiplies base by the result of the same problem with
exponent one smaller. Trace power(2, 3) by hand, the same way the lesson traced factorial(5), before trusting
your code.