# HG changeset patch
# User Christian Urban <urbanc@in.tum.de>
# Date 1511514653 0
# Node ID 15f1fca879c5b08c2d7f8c3a5eba5d3369bcf48e
# Parent  cc6d036401f4ab97b7534d0acb55bbf052140b07
updated

diff -r cc6d036401f4 -r 15f1fca879c5 cws/cw03.pdf
Binary file cws/cw03.pdf has changed
diff -r cc6d036401f4 -r 15f1fca879c5 cws/cw03.tex
--- a/cws/cw03.tex	Fri Nov 24 08:58:11 2017 +0000
+++ b/cws/cw03.tex	Fri Nov 24 09:10:53 2017 +0000
@@ -421,16 +421,16 @@
   integers to integers. The empty memory is represented by
   \texttt{Map()}, that is nothing is stored in the
   memory. \texttt{Map(0 -> 1, 2 -> 3)} clearly has stored \texttt{1}
-  at memory location \texttt{0}, at \texttt{2} it stores
+  at memory location \texttt{0}; at \texttt{2} it stores
   \texttt{3}. The convention is that if we query the memory at a
-  location that is not defined in the \texttt{Map} we return
+  location that is not defined in the \texttt{Map}, we return
   \texttt{0}. Write a function, \texttt{sread}, that takes a memory (a
   \texttt{Map}) and a memory pointer (an \texttt{Int}) as argument,
   and safely reads the corresponding memory location. If the map is not
-  defined at the memory pointer it returns \texttt{0}.
+  defined at the memory pointer, \texttt{sread} returns \texttt{0}.
 
   Write another function \texttt{write}, which takes a memory, a
-  memory pointer and a integer value as argument and updates the map
+  memory pointer and an integer value as argument and updates the map
   with the value at the given memory location. As usual the map is not
   updated `in-place' but a new map is created with the same data,
   except the value is stored at the given memory pointer.\hfill[1 Mark]
@@ -454,7 +454,7 @@
   \texttt{--[..+>--]\barbelow{,}>,++}
   \end{center}
 
-  meaning it jumps after the loop. Similarly, if you in 8th position
+  meaning it jumps to after the loop. Similarly, if you in 8th position
   then \texttt{jumpLeft} is supposed to jump to just after the opening
   bracket (that is jumping to the beginning of the loop):
 
@@ -465,7 +465,7 @@
   \end{center}
 
   Unfortunately we have to take into account that there might be
-  another opening and closing bracket on the `way' to find the
+  other opening and closing brackets on the `way' to find the
   matching bracket. For example in the brainf*** program
 
   \begin{center}
@@ -474,8 +474,8 @@
 
   we do not want to return the index for the \texttt{'-'} in the 9th
   position, but the program counter for \texttt{','} in 12th
-  position. The easiest to find out whether a bracket is matched is to
-  use levels (which are the third argument in \texttt{jumpLeft} and
+  position. The easiest to find out whether a bracket is matched is by
+  using levels (which are the third argument in \texttt{jumpLeft} and
   \texttt{jumpLeft}). In case of \texttt{jumpRight} you increase the
   level by one whenever you find an opening bracket and decrease by
   one for a closing bracket. Then in \texttt{jumpRight} you are looking
@@ -507,16 +507,16 @@
 
 \item[(2c)] Write a recursive function \texttt{run} that executes a
   brainf*** program. It takes a program, a program counter, a memory
-  counter and a memory as arguments. If the program counter is outside
+  pointer and a memory as arguments. If the program counter is outside
   the program string, the execution stops and \texttt{run} returns the
   memory. If the program counter is inside the string, it reads the
-  corresponding character and updates the program counter \texttt{pc}, memory
-  pointer \texttt{mp} and memory \texttt{mem} according to the rules shown
-  in Figure~\ref{comms}. It the calls recursively \texttt{run} with the updated
-  data.
+  corresponding character and updates the program counter \texttt{pc},
+  memory pointer \texttt{mp} and memory \texttt{mem} according to the
+  rules shown in Figure~\ref{comms}. It then calls recursively
+  \texttt{run} with the updated data.
 
   Write another function \texttt{start} that calls \texttt{run} with a
-  given brainfu** program and memory, and the program counter and memory counter
+  given brainfu** program and memory, and the program counter and memory pointer
   set to~$0$. Like \texttt{run} it returns the memory after the execution
   of the program finishes. You can test your brainf**k interpreter with the
   Sierpinski triangle or the Hello world programs or have a look at
@@ -584,8 +584,8 @@
       \hline                 
     \end{tabular}
   \end{center}
-  \caption{The rules for how commands in the brainf*** language update the program counter,
-    memory counter and memory.\label{comms}}
+  \caption{The rules for how commands in the brainf*** language update the program counter \texttt{pc},
+    memory pointer \texttt{mp} and memory \texttt{mem}.\label{comms}}
   \end{figure}
 \end{itemize}\bigskip