C++ :: Fixed Point Int Min Value

I am reading about positive and negative infinity in c++ and i am trying to implement them in a fixed point math arthimethic implementation

I can see that max of a int will be equal to std::numeric_limits<int>::max();
and min value of the int will be equal to std::numeric_limits<int>::min();
in c++

Here as i am defining the int max and int min manually in my fixed point math implementation, my doubt is
int min = -int max; or int min = -int max -1; ?