Merge fa6e2d162d into 3e5b5a51d1

Added C, C# and C++ books

.github/workflows/check-urls.yml

@@ -74,14 +74,17 @@ jobs:
       fail-fast: false
     steps:
       - name: Checkout
+        if: ${{ endsWith(matrix.file, '.yml') || endsWith(matrix.file, '.md') }}
         uses: actions/checkout@v4
         with:
           fetch-depth: ${{ needs.get-changed-files.outputs.fetch-depth }}
       - name: Setup Ruby v2.6
+        if: ${{ endsWith(matrix.file, '.yml') || endsWith(matrix.file, '.md') }}
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.6
       - name: Install awesome_bot
+        if: ${{ endsWith(matrix.file, '.yml') || endsWith(matrix.file, '.md') }}
         run: |
           gem install awesome_bot
       - name: Set output
@@ -101,6 +104,7 @@ jobs:
 
           echo "FILEPATH=${file_path}" >> "$GITHUB_OUTPUT"
       - name: "Check URLs of file: ${{ matrix.file }}"
+        if: ${{ endsWith(matrix.file, '.yml') || endsWith(matrix.file, '.md') }}
         run: |
           awesome_bot "${{ matrix.file }}" --allow-redirect --allow-dupe --allow-ssl || true;
       - uses: actions/upload-artifact@v4

books/free-programming-books-de.md

@@ -66,6 +66,7 @@
 
 ### C
 
+* [c-A Book on C : AL Kelley](https://karadev.net/uroci/filespdf/files/a%20book%20on%20c.pdf) (PDF)
 * [C-HowTo: Programmieren lernen mit der Programmiersprache C](https://www.c-howto.de) - Elias Fischer (HTML)
 * [C-Programmierung](https://de.wikibooks.org/wiki/C-Programmierung) - Wikibooks (HTML)
 * [C von A bis Z](http://openbook.rheinwerk-verlag.de/c_von_a_bis_z) - Jürgen Wolf (Online)
@@ -75,12 +76,14 @@
 ### <a id="csharp"></a>C\#
 
 * [Einführung in das Programmieren mit C#](https://www.uni-trier.de/universitaet/wichtige-anlaufstellen/zimk/downloads-broschueren/programmierung/c) - Bernhard Baltes-Götz (PDF)
+* [FUNDAMENTALS OF COMPUTER PROGRAMMING WITH C#](https://introprogramming.info/wp-content/uploads/2013/07/Books/CSharpEn/Fundamentals-of-Computer-Programming-with-CSharp-Nakov-eBook-v2013.pdf) (PDF)
 * [Programmieren in C#: Einführung](http://www.highscore.de/csharp/einfuehrung)
 * [Visual C# 2012](http://openbook.rheinwerk-verlag.de/visual_csharp_2012) - Andreas Kühnel (Online)
 
 
 ### <a id="cpp"></a>C++
 
+* [A Complete Guide to Programming in C++](https://www.idpoisson.fr/volkov/C++.pdf) (PDF)
 * [Die Boost C++ Bibliotheken](http://dieboostcppbibliotheken.de) - Boris Schäling (Online)
 * [Lean Testing für C++-Programmierer (2018)](https://www.assets.dpunkt.de/openbooks/Openbook_Lean_Testing.pdf) - Andreas Spillner, Ulrich Breymann (PDF)
 * [Programmieren in C++: Aufbau](http://www.highscore.de/cpp/aufbau)