#### Power Using Recursion

P
p
```"""
== Raise base to the power of exponent using recursion ==
Input -->
Enter the base: 3
Enter the exponent: 4
Output  -->
3 to the power of 4 is 81
Input -->
Enter the base: 2
Enter the exponent: 0
Output -->
2 to the power of 0 is 1
"""

def power(base: int, exponent: int) -> float:
"""
Calculate the power of a base raised to an exponent.

>>> power(3, 4)
81
>>> power(2, 0)
1
>>> all(power(base, exponent) == pow(base, exponent)
...     for base in range(-10, 10) for exponent in range(10))
True
>>> power('a', 1)
'a'
>>> power('a', 2)
Traceback (most recent call last):
...
TypeError: can't multiply sequence by non-int of type 'str'
>>> power('a', 'b')
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for -: 'str' and 'int'
>>> power(2, -1)
Traceback (most recent call last):
...
RecursionError: maximum recursion depth exceeded
"""
return base * power(base, (exponent - 1)) if exponent else 1

if __name__ == "__main__":
from doctest import testmod

testmod()
print("Raise base to the power of exponent using recursion...")
base = int(input("Enter the base: ").strip())
exponent = int(input("Enter the exponent: ").strip())
result = power(base, abs(exponent))
if exponent < 0:  # power() does not properly deal w/ negative exponents
result = 1 / result
print(f"{base} to the power of {exponent} is {result}")
```  