Why does this counter (class instance) work properly and doesn't re-initialize at every recursion occurrence? (Python 3.8)

Question

I wanted to count the number of recursion occurrence my binary search would require to find the right item (100). I implemented this Counter class, I thought that it wouldn't work but I gave it a try as an experiment. I thought that I would re-set so to speak (or "overwrite") the previous instantiation, but it doesn't seem to be the case as the counter seem to work.

I have three questions here:

1. Is there a better way to implement a counter for this specific search case?
2. Why is the previous instantiation not overwritten at each recursion occurrence?
3. Am I using the right vocabulary when I say "recursion occurrence"?

from dataclasses import dataclass

@dataclass
class Counter:
    c = 0

    
def binary_search(container, item, left, right):
    
    count = Counter
    count.c +=1
    
    print("count: ", count.c)
    
    # first base case - search misses
    if right < left:
        return -1
    
    # generate the index of the middle item
    middle_index = (left + right) // 2
    
    # we have found the item
    if container[middle_index] == item:
        return middle_index
    
    # have to check whether the middle_item is smaller or greater
    # the item is in the left subèarray
    elif container[middle_index] > item:
        print('Checking items on the left. . .')
        # we can discard the right side of the array (items greater than the middle item)
        return binary_search(container, item, left, middle_index-1)
    
    elif container[middle_index] < item:
        print('Checking items on the right. . .')
        return binary_search(container, item, middle_index+1, right)
        

    

nums = [-5,-4,0,2,4,6,8,100,500]

print(binary_search(nums, 100,0 ,len(nums)-1))

Result:

count:  1
Checking items on the right. . .
count:  2
Checking items on the right. . .
count:  3
7

Thank you

Answer 1

Regarding your question 2: You are not creating an instance of class Counter , but instead refer to the class itself:

count = Counter
count.c +=1

This means, count.c is always the same variable. If instead you write

count = Counter()
count.c +=1

then count.c is always a 'fresh' variable.