What is the most effective way for float and double comparison?

Question

What would be the most efficient way to compare two `double` or two `float` values?

Simply doing this is not correct:

bool CompareDoubles1 (double A, double B)
  {
    return A == B;
  }

But something like:

bool CompareDoubles2 (double A, double B) 
  {
    diff = A - B;
    return (diff < EPSILON) && (-diff < EPSILON);
  }

Seems to waste processing.

Does anyone know a smarter float comparer?

Patrick B. · Accepted Answer

No, go ahead and compare the difference against some EPSILON value...It is much more reliable and worth the cost of the overhead

1 Expert Answer