Scala : rename files in sandbox

1 files changed, 30 insertions, 0 deletions

diff --git a/Scala/sandbox/1-recursion.scala b/Scala/sandbox/1-recursion.scala
new file mode 100644
index 0000000..5488aea
--- /dev/null
+++ b/Scala/sandbox/1-recursion.scala
@@ -0,0 +1,30 @@
+
+object Recursion {
+
+  // Tail recursion - tail calls
+  // the function calls itself (or another one) as last action
+  // -> the function's stack frame can be reused!
+  // -> this is as efficient as a loop
+  def gcd(a: Int, b: Int): Int =
+    if (b == 0) a else gcd(b, a % b)
+
+  // there is still the multiplication to be performed
+  // -> the stack frame can't be reused
+  def fact(n: Int): Int =
+    if (n == 0) 1 else n * fact(n - 1)
+
+  // tail recursive version of factorial
+  def factr(n: Int): Int = {
+    def factIter(acc: Int, n: Int): Int =
+      if (n == 0) acc else factIter(acc * n, n - 1)
+    factIter(1, n)
+  }
+
+  def run = {
+    println("Recursion")
+    println(gcd(21, 56))
+    println(fact(4))
+    println(factr(4))
+  }
+
+}