-s doesn't accept an int

[bacalec]

Hello,
Hhen parsing option -s: its parameter is parsed as string line 218
later it's assigned without a cast line 53
then it's compared to string now and (in that case it's overwritten with an int) or it's verified that it can be cast to a positive integer line 72
So far so good.

Problem is that it's not cast to an int when trying to add it to window_second line 103 and when comparing it to end time line 108
A fix consist in casting it to an int in these lines

Another option maybe more consistent with what is done when it's now would consist in overwriting the string by an int asap.