[SCALA-490] Rounding Decimals (#1537)

* [SCALA-490] Rounding Decimals

* [SCALA-490] Optimized imports

* [SCALA-490] Fixed package names

---------

Co-authored-by: Callum Gibbons <[email protected]>

Author: cawpat

build.sbt

@@ -127,6 +127,14 @@ lazy val scala_core_numbers =
       libraryDependencies += "org.scalatestplus" %% "scalacheck-1-17" % "3.2.18.0" % Test
     )
 
+lazy val scala_core_numbers_2 =
+  (project in file("scala-core-modules/scala-core-numbers-2"))
+    .settings(
+      name := "scala-core-numbers",
+      libraryDependencies ++= scalaTestDeps,
+      scalaVersion := scala3Version
+    )
+
 lazy val scala_core_io = (project in file("scala-core-modules/scala-core-io"))
   .settings(
     name := "scala-core-io",

scala-core-modules/scala-core-numbers-2/src/main/scala/com/baeldung/scala/roundingdecimals/RoundingDecimals.scala

@@ -0,0 +1,12 @@
+package com.baeldung.scala.roundingdecimals
+
+object RoundingDecimals {
+  def roundUp(decimal: Double): Int =
+    math.ceil(decimal).toInt
+
+  def roundDown(decimal: Double): Int =
+    math.floor(decimal).toInt
+
+  def roundToNearestWhole(decimal: Double): Int =
+    math.round(decimal).toInt
+}

scala-core-modules/scala-core-numbers-2/src/test/scala/com/baeldung/scala/roundingdecimals/RoundingDecimalsUnitTest.scala

@@ -0,0 +1,29 @@
+package com.baeldung.scala.roundingdecimals
+
+import com.baeldung.scala.roundingdecimals.RoundingDecimals
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+
+class RoundingDecimalsUnitTest extends AnyWordSpec with Matchers {
+
+  "RoundingDecimals" should {
+    "Always round literals down" in {
+      3 / 4 shouldBe 0
+    }
+    "Always round up in roundUp" in {
+      RoundingDecimals.roundUp(1.1) shouldBe 2
+      RoundingDecimals.roundUp(1.5) shouldBe 2
+      RoundingDecimals.roundUp(1.9) shouldBe 2
+    }
+    "Always round down in roundDown" in {
+      RoundingDecimals.roundDown(1.1) shouldBe 1
+      RoundingDecimals.roundDown(1.5) shouldBe 1
+      RoundingDecimals.roundDown(1.9) shouldBe 1
+    }
+    "Always round to nearest in roundDown" in {
+      RoundingDecimals.roundToNearestWhole(1.1) shouldBe 1
+      RoundingDecimals.roundToNearestWhole(1.5) shouldBe 2
+      RoundingDecimals.roundToNearestWhole(1.9) shouldBe 2
+    }
+  }
+}