Understanding - Advanced, exercise 35

Text

The variable my_mat_string contains the string of a 10-digit matriculation number (e.g. "0000123456"). What is the value returned by calling the function cnt as shown as follows: cnt(my_mat_string).

def cnt(mat_string):
    result = 0

    if len(mat_string) > 0:
        n = int(mat_string[0])

        if n % 2 == 0:
            return 1 + cnt(mat_string[1:])
        else:
            return -1 + cnt(mat_string[1:])
    
    return result

Hints

The function cnt is an recursive function that, at every call, reduces the input of one character.

Additional material

The runnable Python file is available online. You can run it executing the command python exercise_35.py in a shell, and then following the instructions on screen to specify the intended input.