Strange behaviour of if

Question

Could you, please, explain to me how can be -6 more than 100001?
Why is the output of this code as it is?
Is it something with signed/unsigned comparison?
How to fix the problem?
Thanks for help.

https://code.sololearn.com/cVT6c8RaVyWw/?ref=app

Answer 1

size returns an unsigned int so your -6 is converted to unsigned int for the compare becoming the bigger number. Use:
if (i>=(int)fin.size())
to force the signed compare.

Answer 2

The size() method returns a value of std::size_type, a data type that cannot take negative values (which makes sense since a containers size cannot be less than 0). In order to compare the two values, the compiler casts i from int to std::size_type by flipping all bits, leaving a way higher binary value than 100001.