Advanced Functions

def divide(a, b):
    quotient = a // b
    remainder = a % b
    return quotient, remainder

q, r = divide(17, 5)

def power(base, exp=2):
    return base ** exp

power(5)      # 5^2 = 25
power(5, 3)   # 5^3 = 125

x = 10  # Global variable

def func():
    x = 5  # Local variable
    print(x)  # 5

func()
print(x)  # 10

def is_prime(num):
    if num < 2:
        return False
    for i in range(2, num):
        if num % i == 0:
            return False
    return True

def fibonacci(n):
    if n <= 1:
        return n
    return fibonacci(n-1) + fibonacci(n-2)