Python begginer - Can someone tell me why this loop don\'t finish?

Question

def is_power_of_two(n):
  # Check if the number can be divided by two without a remainder
  while n % 2 == 0:
    n = n / 2
  # If after dividing by two the number is 1, it's a power of two
  if n == 1:
    return True
  if n != 0:
    return False

print(is_power_of_two(0)) # Should be False
print(is_power_of_two(1)) # Should be True
print(is_power_of_two(8)) # Should be True
print(is_power_of_two(9)) # Should be False

This is a excercice from Coursera's Python course. I don't know why it don't finish when n=0.

Answer 1

while n % 2 == 0: will turns out to be a infinate loop.

This happening because

First number input is 0

while n % 2 == 0: ---> 0 ==0 --> True

While True:
    #This is infinate loop.

Code correction

To avoid this check if n is zero or not before while.

def is_power_of_two(n):

  if n ==0:
      return False
  # Check if the number can be divided by two without a remainder
  while n % 2 == 0:
    n = n / 2
  # If after dividing by two the number is 1, it's a power of two
  if n == 1:
    return True
  if n != 0:
    return False



print(is_power_of_two(0)) # Should be False
print(is_power_of_two(1)) # Should be True
print(is_power_of_two(8)) # Should be True
print(is_power_of_two(9)) # Should be False

Gives #

False
True
True
False