Write a python function proddigits() that inputs a positive integer number and returns the product of digits of that number. For example, if the input is 422, the function should return 16 (which is equal to 4×2×2 ).

Here's one way to write the `proddigits()` function in Python:

def proddigits(num):
    """Returns the product of the digits in a positive integer number."""
    product = 1  # start with a product of 1
    while num > 0:
        digit = num % 10  # extract the rightmost digit
        product *= digit  # multiply the product by the digit
        num //= 10  # remove the rightmost digit from the number
    return product

You can call this function with a positive integer argument to get the product of its digits:

print(proddigits(422))  # Output: 16
print(proddigits(12345))  # Output: 120
print(proddigits(987654321))  # Output: 362880

The function works by iterating over the digits of the input number using a while loop. In each iteration, it extracts the rightmost digit using the modulo operator (`%`) and multiplies the product by that digit. Then it removes the rightmost digit from the number using integer division (`//`). The loop continues until there are no more digits left in the number. Finally, the function returns the product of all the digits.