Why is this giving me an infinite loop?

[wlsa]

def gcdIter(a, b):
    '''
    a, b: positive integers
    
    returns: a positive integer, the greatest common divisor of a & b.
    '''
    # Your code here
    r=1
    GCD=1
    smaller=b
    if a>b is True:
        b=smaller
    if b>a is True:
        a=smaller
    while smaller >=r:
        if a%r==0 and b%r==0:
            r=GCD
            r+=1
        else:
            r+=1
    print(GCD)
gcdIter(2,4)

I know this propably isn't the most efficient way of finding the greatest common denominator, but I don't understand how I'm getting an infinite loop, from what I can tell I have made "r" continually increase by 1 until it is greater than the smallest given integer.

I figured it out, I changed line 10 to "smaller=1"

[metulburr]

I figured it out, I changed line 10 to "smaller=1"

also the is True is redundant here. The result of X>Y returns True or False.

[wlsa]

Also, what was wrong with line 10? I don't understand why I had to change that.

[ichabod801]

Because your code doesn't work. Walk through the original code. Smaller gets set to b (4). Since b > a, a gets set to smaller (4). First loop smaller >= r (4 >= 1). The conditional is triggered, because anything % 1 = 0. So r is set to GCD (1), and then one is added to it. Second smaller >= r (4 >= 2). The conditional is triggered again, because both a and b are 4 and 4 % 2 == 0. So r is set to GCD (still 1) and one is added to it. Third loop (and every loop thereafter) 4 >= 2. r is always 2 when the loop is checked.

By changing smaller = 1, on the second loop you get 1 >= 2, which is False. So you get out of the infinite loop. but that doesn't mean the answer you're getting is correct.

[cyberpatje]

I'm new to programming, I don't get your code.
You can solve it with Euclidean algorithm.