Python Data Structures and Algorithms - Recursion: Factorial of a non-negative integer

Last update on July 28 2025 12:57:14 (UTC/GMT +8 hours)

4. Factorial Using Recursion

Write a Python program to get the factorial of a non-negative integer using recursion.

Sample Solution:

Python Code:

# Define a function named factorial that calculates the factorial of a given number 'n'
def factorial(n):
    # Check if 'n' is less than or equal to 1
    if n <= 1:
        # If 'n' is 1 or less, return 1 (base case for factorial)
        return 1
    else:
        # If 'n' is greater than 1, recursively call the factorial function
        # to calculate the factorial of (n - 1) and multiply the result by 'n'
        return n * factorial(n - 1)

# Print the result of calling the factorial function with the input value 5
print(factorial(5))

Sample Output:

120

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to compute the factorial of a non-negative integer using a basic recursive approach.
• Write a Python program to implement tail recursion for calculating factorial and compare its efficiency.
• Write a Python program to calculate factorial recursively with error handling for negative inputs.
• Write a Python program to recursively compute factorial and use it to solve a combinations problem (n choose k).

Go to:

• Python Recursion Exercises Home ↩
• Python Exercises Home ↩

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