Scala : add recfun

5 files changed, 143 insertions, 0 deletions

diff --git a/Scala/recfun/src/main/scala/common/package.scala b/Scala/recfun/src/main/scala/common/package.scala
new file mode 100644
index 0000000..f1c74c3
--- /dev/null
+++ b/Scala/recfun/src/main/scala/common/package.scala
@@ -0,0 +1,40 @@
+import java.io.File
+
+package object common {
+
+  /** An alias for the `Nothing` type.
+   *  Denotes that the type should be filled in.
+   */
+  type ??? = Nothing
+
+  /** An alias for the `Any` type.
+   *  Denotes that the type should be filled in.
+   */
+  type *** = Any
+
+  
+  /**
+   * Get a child of a file. For example,
+   * 
+   *   subFile(homeDir, "b", "c")
+   * 
+   * corresponds to ~/b/c
+   */
+  def subFile(file: File, children: String*) = {
+    children.foldLeft(file)((file, child) => new File(file, child))
+  }
+
+  /**
+   * Get a resource from the `src/main/resources` directory. Eclipse does not copy
+   * resources to the output directory, then the class loader cannot find them.
+   */
+  def resourceAsStreamFromSrc(resourcePath: List[String]): Option[java.io.InputStream] = {
+    val classesDir = new File(getClass.getResource(".").toURI)
+    val projectDir = classesDir.getParentFile.getParentFile.getParentFile.getParentFile
+    val resourceFile = subFile(projectDir, ("src" :: "main" :: "resources" :: resourcePath): _*)
+    if (resourceFile.exists)
+      Some(new java.io.FileInputStream(resourceFile))
+    else
+      None
+  }
+}
diff --git a/Scala/recfun/src/main/scala/recfun/Main.scala b/Scala/recfun/src/main/scala/recfun/Main.scala
new file mode 100644
index 0000000..277aa1a
--- /dev/null
+++ b/Scala/recfun/src/main/scala/recfun/Main.scala
@@ -0,0 +1,28 @@
+package recfun
+import common._
+
+object Main {
+  def main(args: Array[String]) {
+    println("Pascal's Triangle")
+    for (row <- 0 to 10) {
+      for (col <- 0 to row)
+        print(pascal(col, row) + " ")
+      println()
+    }
+  }
+
+  /**
+   * Exercise 1
+   */
+  def pascal(c: Int, r: Int): Int = ???
+
+  /**
+   * Exercise 2
+   */
+  def balance(chars: List[Char]): Boolean = ???
+
+  /**
+   * Exercise 3
+   */
+  def countChange(money: Int, coins: List[Int]): Int = ???
+}
diff --git a/Scala/recfun/src/test/scala/recfun/BalanceSuite.scala b/Scala/recfun/src/test/scala/recfun/BalanceSuite.scala
new file mode 100644
index 0000000..c040682
--- /dev/null
+++ b/Scala/recfun/src/test/scala/recfun/BalanceSuite.scala
@@ -0,0 +1,27 @@
+package recfun
+
+import org.scalatest.FunSuite
+
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+class BalanceSuite extends FunSuite {
+  import Main.balance
+
+  test("balance: '(if (zero? x) max (/ 1 x))' is balanced") {
+    assert(balance("(if (zero? x) max (/ 1 x))".toList))
+  }
+
+  test("balance: 'I told him ...' is balanced") {
+    assert(balance("I told him (that it's not (yet) done).\n(But he wasn't listening)".toList))
+  }
+
+  test("balance: ':-)' is unbalanced") {
+    assert(!balance(":-)".toList))
+  }
+
+  test("balance: counting is not enough") {
+    assert(!balance("())(".toList))
+  }
+}
diff --git a/Scala/recfun/src/test/scala/recfun/CountChangeSuite.scala b/Scala/recfun/src/test/scala/recfun/CountChangeSuite.scala
new file mode 100644
index 0000000..0da3359
--- /dev/null
+++ b/Scala/recfun/src/test/scala/recfun/CountChangeSuite.scala
@@ -0,0 +1,26 @@
+package recfun
+
+import org.scalatest.FunSuite
+
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+class CountChangeSuite extends FunSuite {
+  import Main.countChange
+  test("countChange: example given in instructions") {
+    assert(countChange(4,List(1,2)) === 3)
+  }
+
+  test("countChange: sorted CHF") {
+    assert(countChange(300,List(5,10,20,50,100,200,500)) === 1022)
+  }
+
+  test("countChange: no pennies") {
+    assert(countChange(301,List(5,10,20,50,100,200,500)) === 0)
+  }
+
+  test("countChange: unsorted CHF") {
+    assert(countChange(300,List(500,5,50,100,20,200,10)) === 1022)
+  }
+}
diff --git a/Scala/recfun/src/test/scala/recfun/PascalSuite.scala b/Scala/recfun/src/test/scala/recfun/PascalSuite.scala
new file mode 100644
index 0000000..58c899e
--- /dev/null
+++ b/Scala/recfun/src/test/scala/recfun/PascalSuite.scala
@@ -0,0 +1,22 @@
+package recfun
+
+import org.scalatest.FunSuite
+
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+class PascalSuite extends FunSuite {
+  import Main.pascal
+  test("pascal: col=0,row=2") {
+    assert(pascal(0,2) === 1)
+  }
+
+  test("pascal: col=1,row=2") {
+    assert(pascal(1,2) === 2)
+  }
+
+  test("pascal: col=1,row=3") {
+    assert(pascal(1,3) === 3)
+  }
+}