How do I fix sum of digits of a number code not entering an infinite loop?

I don’t understand why it enters an infinite loop. I stated that: if a % 10 == 0: it should break the loop but it doesn’t seem to do so. Could someone explain why this happens and why it is not correct and the solution. Thank you!

a = int(input())
total = 0
while a>0:
    rest = a % 10
    total += rest
    if rest == 0:
        break

print(total)

>Solution :

It is running for infinite times because of logical error. value of a is not decreasing.
you are checking for remainder, suppose value of a is 230. then at first iteration rest will be 0 and your output will be also 0 (correct sum will be 5).

correct code will be :-

a = int(input())
total = 0
while a>0:
    rest = a % 10
    total += rest
    a=a//10
print(total)