Write a program to print all digits of a given number by using a recursive function.

Here's the Python code to print all digits of a given number using a recursive function:

def print_digits(n):
    if n < 10:
        print(n)
    else:
        print_digits(n // 10)
        print(n % 10)

# Example usage:
print_digits(12345)  # Output: 1 2 3 4 5

In this code, the `print_digits` function takes an integer `n` as input. If `n` is less than 10, we simply print it. Otherwise, we first call the `print_digits` function recursively with `n // 10`, which gives us all the digits except for the last one. Then, we print the last digit by computing `n % 10`. This way, we print the digits in reverse order (from right to left).