Sync

Task/Stack/Scala/stack-2.scala

@@ -0,0 +1,9 @@
+import collection.mutable.{ Stack => Stak }
+
+class Stack[T] extends Stak[T] {
+  override def pop: T = {
+    if (this.length == 0) error("Can't Pop from an empty Stack.")
+    else super.pop
+  }
+  def peek: T = this.head
+}