func classifyFloat(x float64) string {
	switch {
	case math.IsNaN(x):
		return "NaN"
	case math.IsInf(x, 1):
		return "+Inf"
	case math.IsInf(x, -1):
		return "-Inf"
	case x == 0:
		return "Zero"
	case x > 0:
		return "Positive"
	default:
		return "Negative"
	}
}