/*
* ==========================================================
* Title: Safe Floating-Point Comparison in Scala
* ==========================================================
*
* Floating-point numbers should not be compared directly
* with == because rounding errors can occur during
* mathematical operations.
*
* Recommended approach:
* Compare values using a small tolerance (epsilon).
*/
/**
* Utility methods for floating-point comparisons.
*/
object NumberUtils {
// Default tolerance for Double comparisons
private val DefaultEpsilon: Double = 1e-9
/**
* Returns true when two Double values are
* sufficiently close to be considered equal.
*/
def approximatelyEqual(
a: Double,
b: Double,
epsilon: Double = DefaultEpsilon
): Boolean =
math.abs(a - b) <= epsilon
}
/**
* Application entry point.
*
* Using @main is the recommended approach in Scala 3
* and avoids deprecation warnings associated with App.
*/
@main
def floatingPointComparisonDemo(): Unit = {
val expected = 0.3
val actual = 0.1 + 0.2
println(s"Expected value: $expected")
println(s"Actual value: $actual")
// Direct comparison is unreliable
println(s"Using == : ${expected == actual}")
// Safe comparison using tolerance
println(
s"Using approximatelyEqual : ${
NumberUtils.approximatelyEqual(expected, actual)
}"
)
}
/*
run:
Expected value: 0.3
Actual value: 0.30000000000000004
Using == : false
Using approximatelyEqual : true
*/
