considering the number as long is it enough??

i think the number may be as long as 1000000 digits
such as 11..1 {there's 1000000 number'1'}.

test: 123
answer is 4
be carefull on test 16

when the last char is '0'
the strlen of char will been dec()

for 123, is the answer suppose to be 3?

no, it's 4