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Python Exercise: Calculate the factorial of a number

Python Functions: Exercise-5 with Solution

Write a Python function to calculate the factorial of a number (a non-negative integer). The function accepts the number as an argument.

Sample Solution-1:

Python Code:

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n-1)
n=int(input("Input a number to compute the factiorial : "))
print(factorial(n))

Sample Output:

Input a number to compute the factiorial : 4                                                                  
24

Pictorial presentation:

Python exercises: Calculate the factorial of a number.

Flowchart:

Flowchart: Python exercises: Calculate the factorial of a number.

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Sample Solution-2:

  • Use recursion.
  • If n is less than or equal to 1, return 1.
  • Otherwise, return the product of n and the factorial of n - 1.
  • Display an error message if n is a negative or a floating point number.

Python Code:

def factorial(n):
  if not ((n >= 0) and (n % 1 == 0)):
    return("Number can't be negative or floating point!")
  return 1 if n == 0 else n * factorial(n - 1)

print("\nFactorial of 5: ",factorial(5))
print("\nFactorial of -12: ",factorial(-12))
print("\nFactorial of 1.22: ",factorial(1.22))
print("\nFactorial of 100: ",factorial(100))

Sample Output:

Factorial of 5:  120

Factorial of -12:  Number can't be negative or floating point!

Factorial of 1.22:  Number can't be negative or floating point!

Factorial of 100:  93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000

Flowchart:

Flowchart: Python exercises: Calculate the factorial of a number.

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:


Python Code Editor:

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Python: Tips of the Day

Decapitalizes the first letter of a string:

Example:

def tips_decapitalize(s, upper_rest=False):
  return s[:1].lower() + (s[1:].upper() if upper_rest else s[1:])
print(tips_decapitalize('PythonTips'))
print(tips_decapitalize('PythonTips', True)) 

Output:

pythonTips
pYTHONTIPS