Python program uses recursion to calculate the factorial of a number

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In this program, you will learn to use recursive functions to calculate the factorial of a number.

To understand this example, you should understand the followingPython programmingTopic:

• Python if ... else statement

• Python function

• Python recursion

The factorial of a number is from1is the product of all integers up to the number.

For example, the factorial6is1*2*3*4*5*6 = 720. Factorial is not defined for negative numbers, the factorial of zero is1、0!= 1.

Source code

# Python program uses recursion to calculate the factorial of a number
def recur_factorial(n):
　　　if n ==　1:
　　　　　　　return n
　　　else:
　　　　　　　return n*recur_factorial(n-1)
num =　7
# Check if the number is negative
if num < 0:
　　　print("Sorry, the factorial of negative numbers does not exist")
elif num == 0:
　　　print("The factorial of 0 is ",1")
else:
　　　print(num, "'s factorial is", recur_factorial(num))

Output result

7　The factorial is　5040

Note:To find the factorial of other numbers, change the value of num.

Here, the number is stored in num. This number will be passed to the recur_factorial() function to calculate the factorial of the number.

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