added appendix with code

901_Appendix_Code.tex

+\chapter{Programmcode}
+  \lstset{
+    language=Python,
+    tabsize=2,
+    rulesepcolor=\color{gray},
+    xleftmargin=00pt,
+    framexleftmargin=00pt,
+    keywordstyle=\color{blue}\bf,
+    commentstyle=\color{gray},
+    stringstyle=\color{red},
+    numbers=left,
+    numberstyle=\tiny,
+    numbersep=5pt,
+    breaklines=true,
+    showstringspaces=false,
+    basicstyle=\fontsize{7}{9}\selectfont\ttfamily,
+    emph={str},emphstyle={\color{magenta}}}
+\section{\texttt{quicksort} in Python}
+  \lstinputlisting[language=Python]{code/quicksort.py}

Datenstrukturen_und_Algorithmen.tex

-\documentclass[ngerman, a4paper, oneside]{scrbook}
+\documentclass[ngerman, a4paper, oneside, appendixprefix]{book}
 \usepackage[ngerman]{babel}
 %encoding
 \usepackage[utf8]{inputenc}
 \usepackage{alphabeta}
 
+%appendix (copied from SE)
+%\usepackage{xpatch}
+%\xapptocmd{\appendix}{%
+%  \addtocontents{toc}{%
+%    \RedeclareSectionCommand[
+%      tocdynnumwidth,
+%      tocentrynumberformat=\tocappendixnumber
+%    ]{chapter}%
+%  }%
+%}{}{\PatchFailed}
+%\newcommand\tocappendixnumber[1]{\chapapp~#1}
 
 %math symbols
 \usepackage{amsmath}
@@ -29,6 +40,9 @@
 \SetEndCharOfAlgoLine{}
 \usepackage{textcomp}
 
+%code listings
+\usepackage{listings}
+
 %figures
 \usepackage{subcaption}
 %internal figures
@@ -45,6 +59,7 @@
 %other
 \usepackage{scrextend}
 %\usepackage{hhline}
+\usepackage{appendix}
 
 %custom macros
 \makeatletter
@@ -62,4 +77,7 @@
 \input{100_Grundlagen}
 \input{200_Sortieralgorithmen}
 \input{300_Datenstrukturen}
+
+\appendix
+\input{901_Appendix_Code}
 \end{document}

code/quicksort.py

+def swap(A,i,j):
+  A[i], A[j] = A[j], A[i]
+  return A
+
+def partition(A):
+  p = A[-1]
+  print("A is {} as partition is called, pivot is {}".format(A, p))
+  i = -1
+  for j in range(len(A)-1):
+    if A[j] <= p:
+      A = swap(A,i+1,j)
+      i += 1
+      print("A is {} after swapping i={} and j={} during partition as {} <= {}".format(A,i,j,A[i],p))
+
+  A = swap(A,i+1,-1)
+  i += 1
+  print("A is {} after swapping {} and {} in final swap in partition, returning A and pivot index {} to quicksort".format(A,i,j,i))
+  return (A,i)
+
+def quicksort(A):
+  print("A is {} as quicksort is called".format(A))
+  if len(A) > 1:
+    A,k = partition(A)
+    print("A is {} after partition, calculating now:  quicksort({}) + [A[{}]] + quicksort({})  ".format(A, A[:k], k, A[k+1:]))
+    return quicksort(A[:k]) + [A[k]] + quicksort(A[k+1:])
+  else:
+    return A
+
+
+A = [7,2,1,8,6,3,5,4] # see https://www.youtube.com/watch?v=MZaf_9IZCrc for step-for-step explanation of the first partition here 
+# A = [34,56,99,46,23,16,23,11,23,56] # a more complex case, might be helpful ...
+A = quicksort(A)
+
+print("A was sorted to {}".format(A))