24 lines
546 B
Markdown
24 lines
546 B
Markdown
---
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title: factorial
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tags: math,recursion,beginner
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---
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Calculates the factorial of a number.
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Use recursion.
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If `num` is less than or equal to `1`, return `1`.
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Otherwise, return the product of `num` and the factorial of `num - 1`.
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Throws an exception if `num` is a negative or a floating point number.
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```py
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def factorial(num):
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if not ((num >= 0) and (num % 1 == 0)):
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raise Exception(
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f"Number( {num} ) can't be floating point or negative ")
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return 1 if num == 0 else num * factorial(num - 1)
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```
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```py
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factorial(6) # 720
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```
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