Python/maths/power_using_recursion.py
Jai Vignesh J 788e4ede9b
Fix doctest power recursion (#10659)
* Added doctests to power_using_recursion.py

* Added doctest to power_using_recursion.py

* Update power_using_recursion.py

* Update power_using_recursion.py

---------

Co-authored-by: Christian Clauss <cclauss@me.com>
2023-10-18 00:50:57 +02:00

54 lines
1.5 KiB
Python

"""
== 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:
"""
>>> 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 doctests 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}")