diff -r 40424bbe109e -r f5ed0fef41b3 progs/lecture1.scala
--- a/progs/lecture1.scala	Thu Nov 10 11:41:50 2016 +0000
+++ b/progs/lecture1.scala	Thu Nov 10 16:10:39 2016 +0000
@@ -68,8 +68,8 @@
 List(1,2,3,4).drop(2).sum
 List(1,2,3,4,3).indexOf(3)
 
-"1,2,3,4,5".split(",").toList
-
+"1,2,3,4,5".split(",").mkString("\n")
+"1,2,3,4,5".split(",3,").mkString("\n")
 
 // Types
 //=======
@@ -93,8 +93,9 @@
 // Smart Strings
 //===============
 
-println(">\n<")
+println(">\n\n<")
 println(""">\n<""")
+println("""">\n<"""")
 
 /* in Java
 val lyrics = "Baa, Baa, Black Sheep \n" +
@@ -148,12 +149,26 @@
 square(6)
 
 
+
+// The general scheme for a function: you have to give a type 
+// to each argument and a return type of the function
+//
+//  def fname(arg1: ty1, arg2: ty2,..., argn: tyn): rty = {
+//    body 
+//  }
+
+
+
 // If control structure
 //======================
 
 def fact(n: Int): Int = 
   if (n == 0) 1 else n * fact(n - 1)
 
+
+fact(5)
+fact(150)
+
 /* boolean operators
  
    ==     equals
@@ -239,19 +254,18 @@
 
 
 
-// with only a side-effect (no list is produced)
+// with only a side-effect (no list is produced),
 // has no "yield"
 
 for (n <- (1 to 10)) println(n)
 
 
-// concurrency (ONLY WORKS IN 2.11.8)
+// concurrency (ONLY WORKS IN SCALA 2.11.8, not in SCALA 2.12.0)
 for (n <- (1 to 10)) println(n)
 for (n <- (1 to 10).par) println(n)
 
 
-
-// for testing time
+// for measuring time
 def time_needed[T](i: Int, code: => T) = {
   val start = System.nanoTime()
   for (j <- 1 to i) code
@@ -270,11 +284,12 @@
 
 import io.Source
 
+// obtaining a webpage
 val url = """http://www.inf.kcl.ac.uk/staff/urbanc/""" 
 Source.fromURL(url)("ISO-8859-1").mkString
 
 
-
+// function for looking up stockmarket data 
 def price_lookup(symbol: String): String = {
   val url = "http://finance.yahoo.com/d/quotes.csv?s=" + symbol + "&f=snl1"
   Source.fromURL(url).mkString.drop(1).dropRight(2)
@@ -292,6 +307,8 @@
 
 // A Web Crawler
 //===============
+//
+// the idea is to look for dead links
 
 import io.Source
 import scala.util.matching.Regex
@@ -330,26 +347,6 @@
 
 
 
-
-// Adding your own methods to Strings
-//====================================
-
-// imagine you want to implement an additional
-// method to strings, like
-//
-//     "HAL".increment
-//
-// you can avoid ugly fudges, like a MyString
-// class by using implicit conversions
-
-
-implicit class MyString(s: String) {
-  def increment = for (c <- s) yield (c + 1).toChar 
-}
-
-"HAL".increment
-
-
 // Further Information
 //=====================