mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
c0acfd46cb
* updating DIRECTORY.md
* pass integer to `math.factorial` in `project_euler/problem_015`
* remove duplicated factorial function
* updating DIRECTORY.md
* Update maths/factorial_iterative.py
Co-authored-by: Christian Clauss <cclauss@me.com>
* Update factorial_iterative.py
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
44 lines
1.1 KiB
Python
44 lines
1.1 KiB
Python
"""Factorial of a positive integer -- https://en.wikipedia.org/wiki/Factorial
|
|
"""
|
|
|
|
|
|
def factorial(number: int) -> int:
|
|
"""
|
|
Calculate the factorial of specified number (n!).
|
|
|
|
>>> import math
|
|
>>> all(factorial(i) == math.factorial(i) for i in range(20))
|
|
True
|
|
>>> factorial(0.1)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: factorial() only accepts integral values
|
|
>>> factorial(-1)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: factorial() not defined for negative values
|
|
>>> factorial(1)
|
|
1
|
|
>>> factorial(6)
|
|
720
|
|
>>> factorial(0)
|
|
1
|
|
"""
|
|
if number != int(number):
|
|
raise ValueError("factorial() only accepts integral values")
|
|
if number < 0:
|
|
raise ValueError("factorial() not defined for negative values")
|
|
value = 1
|
|
for i in range(1, number + 1):
|
|
value *= i
|
|
return value
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|
|
|
|
n = int(input("Enter a positive integer: ").strip() or 0)
|
|
print(f"factorial{n} is {factorial(n)}")
|