includes method
Implementation
bool includes(num comparable) {
// before - read as: if negative, true, if zero test for includes, if positive, false.
int beforeMin = comparable.compareTo(min);
int beforeMax = comparable.compareTo(max);
// Hopefully these complications gain some minor speed,
// dealing with the obvious cases first.
if (beforeMin < 0 || beforeMax > 0) return false;
if (beforeMin > 0 && beforeMax < 0) return true;
if (beforeMin == 0 && includesMin) return true;
if (beforeMax == 0 && includesMax) return true;
return false;
}