Hello Everyone<\/p>\n
Here is a Scala application example that demonstrate how to reverse a singularly linked list.<\/p>\n
\r\n\/* Written by Peter Pilgrim 10th December 2010 *\/\r\npackage uk.co.xenonique.scalaexercises\r\n\r\nimport scala.collection.mutable.StringBuilder\r\nimport java.lang.System\r\n\r\nabstract class LinkedList { }\r\n\r\ncase object EmptyLinked extends LinkedList\r\n\r\ncase class LinkedNode( var value: Int, var next:LinkedList ) extends LinkedList\r\n\r\n\r\n\/**\r\n * Example Scala program that demonstrates an algorithm to reverse a singularly linked list of elements.\r\n *\/\r\n\r\nobject NodeApp {\r\n\r\n def traverse( node: LinkedList ): String = {\r\n def _traverse( node: LinkedList, buf: StringBuilder ): Unit = {\r\n node match {\r\n case b: LinkedNode => {\r\n buf.append( "%d, ".format( b.value ))\r\n _traverse( b.next, buf )\r\n }\r\n case _ =>\r\n }\r\n }\r\n\r\n val buf = new StringBuilder("[");\r\n _traverse( node, buf );\r\n buf.append("]")\r\n buf.toString\r\n }\r\n\r\n def reverse( current: LinkedList ): LinkedList = {\r\n def _reverse( current: LinkedList, parent: LinkedList ): LinkedList = {\r\n println("::>> current="+current+", parent="+parent)\r\n current match {\r\n case b: LinkedNode => {\r\n val revHead = _reverse( b.next, current )\r\n printf( "<<:: b.value=%d, b.next=0x%-8X, \r\n current=0x%-8X, parent=0x%-8X\\n",\r\n b.value, \r\n System.identityHashCode(b.next),\r\n System.identityHashCode(current), \r\n System.identityHashCode(parent) )\r\n b.next = parent\r\n revHead\r\n }\r\n case _ => parent\r\n }\r\n }\r\n \r\n _reverse( current, null)\r\n }\r\n\r\n def main( args: Array[String]) {\r\n\r\n val s = LinkedNode( 1, \r\n LinkedNode( 2, \r\n LinkedNode(3, \r\n LinkedNode( 4, EmptyLinked ))))\r\n print("s="+traverse(s))\r\n val t = reverse(s)\r\n print("t="+traverse(t))\r\n\r\n }\r\n}\r\n\r\n<\/pre>\n <\/p>\n
The example program above demonstrates the following salient points:<\/p>\n
Merry Xmas <\/p>\n","protected":false},"excerpt":{"rendered":"
Hello Everyone Here is a Scala application example that demonstrate how to reverse a singularly linked list. The example program above demonstrates the following salient points: Scala\u2019s syntax for use of case instance classes that reduce the boiler plate and add syntax sugar to ordinary object classes. (LinkedNode) One can declare case object class […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[36,37,38,39,40,6],"tags":[],"_links":{"self":[{"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/posts\/184"}],"collection":[{"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/comments?post=184"}],"version-history":[{"count":5,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/posts\/184\/revisions"}],"predecessor-version":[{"id":185,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/posts\/184\/revisions\/185"}],"wp:attachment":[{"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/media?parent=184"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/categories?post=184"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xenonique.co.uk\/blog\/wp-json\/wp\/v2\/tags?post=184"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}