You are dividing by "zero". STOP DOING THAT.
might be due to automatic memory allocation by the stl lib.
>>> 1.2 - 1.0
>>> 0.19999999999996
It’s a normal case encountered when handling floating-point numbers internally in a
system. It’s a problem caused when the internal representation of floating-point
numbers, which uses a fixed number of binary digits to represent a decimal number. It
is difficult to represent some decimal number in binary, so in many cases, it leads to
small roundoff errors.