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Consider the recursive function for the calculation of a factorial.

def factorial(n):
if n == 1:
return n
else:
return n * factorial(n - 1)
print("The factorial of", 7, "is", factorial(7))
How could the program be modified to print the product of all the even numbers less than 7?

(1 point)
Responses

def factorial(n):
if n <= 1:
return 1
else:
if n % 2 != 0:
return n * factorial(n - 2)
else:
return factorial(n - 1)
print("The answer is", factorial(7))
def factorial(n): if n <= 1: return 1 else: if n % 2 != 0: return n * factorial(n - 2) else: return factorial(n - 1) print("The answer is", factorial(7))

def factorial(n):
if n == 0:
return 1
else:
if n % 2 == 0:
return n * factorial(n - 2)
else:
return factorial(n - 1)
print("The answer is", factorial(7))
def factorial(n): if n == 0: return 1 else: if n % 2 == 0: return n * factorial(n - 2) else: return factorial(n - 1) print("The answer is", factorial(7))

def factorial(n):
if n <= 1:
return n
else:
return n * factorial(n - 2)
print("The answer is", factorial(7))
def factorial(n): if n <= 1: return n else: return n * factorial(n - 2) print("The answer is", factorial(7))

def factorial(n):
if n == 1:
return n
else:
return n * factorial(n - 2)
print("The answer is", factorial(7))

1 answer

To modify the recursive function to print the product of all the even numbers less than 7, we should ensure that the function considers only even numbers and multiplies them appropriately.

The correct modification would remove odd numbers from consideration as well as ensure that the function is correctly terminating for even input. Considering the options provided, the most appropriate snippet is:

def factorial(n):
   if n == 0:
       return 1
   else:
       if n % 2 == 0:
           return n * factorial(n - 2)
       else:
           return factorial(n - 1)
print("The answer is", factorial(7))

Explanation:

  • In this modified function:
    • The base case is set to if n == 0: return 1, which is common for factorial and zero is technically the product of no numbers, often defined as 1.
    • If n is even (n % 2 == 0), it multiplies n by the factorial of n - 2, effectively counting down by 2 to include only even numbers.
    • If n is odd, it simply calls the function on the next lower number (n - 1), effectively skipping it since it won't contribute to the product of even numbers.
  • The print statement will display the product of all even numbers less than or equal to 6 (which are 2, 4, 6).

With this modification, when factorial(7) is called, it calculates 6 * 4 * 2, which equals 48.