--- a/slides/slides10.tex	Wed Dec 04 14:39:32 2019 +0000
+++ b/slides/slides10.tex	Sat Dec 07 00:57:23 2019 +0000
@@ -1,3 +1,4 @@
+% !TEX program = xelatex
 \documentclass[dvipsnames,14pt,t]{beamer}
 \usepackage{../slides}
 \usepackage{../langs}
@@ -50,20 +51,62 @@
   \normalsize
   \begin{center}
   \begin{tabular}{ll}
-  Email:  & christian.urban at kcl.ac.uk\\
-  Office: & N7.07 (North Wing, Bush House)\\
-  Slides: & KEATS (also home work is there)\\
+    Email:  & christian.urban at kcl.ac.uk\\
+    Office Hours: & Thursdays 12 -- 14\\
+    Location: & N7.07 (North Wing, Bush House)\\
+    Slides \& Progs: & KEATS (also homework is there)\\  
   \end{tabular}
   \end{center}
 
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
+\begin{frame}[c,fragile]
+
+
+\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-6mm]
+def fact(n: Int) : Int = {
+  if (n == 0) 1 else n * fact(n - 1) 
+}
+
+
+def factC(n: Int, ret: Int => Int) : Int = {
+  if (n == 0) ret(1) 
+  else factC(n - 1, x => ret(n * x)) 
+}
+
+fact(10)
+factC(10, identity)
+\end{lstlisting}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
+\begin{frame}[c,fragile]
+
+
+\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-6mm]
+def fibC(n: Int, ret: Int => Int) : Int = {
+  if (n == 0 || n == 1) ret(1) else
+  fibC(n - 1,
+       r1 => fibC(n - 2,
+        r2 => ret(r1 + r2)))
+}
+
+fibC(10, identity)
+\end{lstlisting}
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
 
-  \Large\bf Are there more strings in \bl{$L(a^*)$} or
+  \Large\bf Are there more strings in \\ \hfill\bl{$L(a^*)$} or
   \bl{$L((a + b)^*)$}?
 
 \end{frame}
@@ -71,6 +114,25 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[c]
+\frametitle{Can you remember this HW?}
+
+  \begin{itemize}
+  \item (1) How many basic regular expressions are there to match
+      the string \bl{$abcd$}? 
+  \item (2) How many if they cannot include
+      \bl{$\ONE$} and \bl{$\ZERO$}? 
+  \item (3) How many if they are also not
+      allowed to contain stars? 
+  \item (4) How many if they are also
+      not allowed to contain \bl{$\_ + \_$}?
+   \end{itemize}  
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
 
 \Large\bf There are more problems, than there are
 programs.\bigskip\bigskip\pause\\