How to correctly and standardly compare floats?

Question

Every time I start a new project and when I need to compare some float or double variables I write the code like this one:

if (fabs(prev.min[i] - cur->min         


        

Answer 1

Here is a c++11 implementation of @geotavros 's solution. It makes use of the new std::numeric_limits::epsilon() function and the fact that std::fabs() and std::fmax() now have overloads for float, double and long float.

template
static bool AreEqual(T f1, T f2) { 
  return (std::fabs(f1 - f2) <= std::numeric_limits::epsilon() * std::fmax(std::fabs(f1), std::fabs(f2)));
}