PHYS4070-L01

# Quick note on plagiarism

* Comparing/discussing answers is encouraged
                * solving problems with others and working in groups is good     
                * However, copy and paste from others OR the internet is not.
                
                <br>

## Stackoverflow, internet sources
                * Copying small code snippets, e.g., for syntax is fine. 
                * Copying large chunks of someone else's solution is not. 
                * If you copy and paste and then cosmetically change the code this is also plagiarism.
                * Use your judgement

<br>

## Provided examples
                * You may use any of examples we explicitly give you in the labs etc.
                * Plus many examples: [github.com/benroberts999/cpp-cheatsheet](https://www.github.com/benroberts999/cpp-cheatsheet)

<br>
            
              ## AI
                * Great for debugging small code snippets, not great at solving large problems

# Info/Resources

<h2>cpp "cheat-sheet"</h2>
                <ul>
                  <li>
                    <a href="https://www.github.com/benroberts999/cpp-cheatsheet" target="_blank">
                      github.com/benroberts999/cpp-cheatsheet
                    </a>
                  </li>
                  <li>A list of simple and advanced examples: free to use.</li>
                </ul>
                
                <br><br><br><br><br><br>
                
                <h2>Online Tutorials</h2>
                <ul>
                  <li>
                    Highly recommend:
                    <a href="https://hackingcpp.com/" target="_blank">hackingcpp.com</a>
                  </li>
                  <li>
                    <a href="https://hackingcpp.com/cpp/beginners_guide.html" target="_blank">
                      hackingcpp.com/cpp/beginners_guide
                    </a>
                  </li>
                </ul>

</div>
              <div style="text-align: center; float: right; width: 50%">
                <h2>Technical Documentation</h2>
                <ol>
                  <li>
                    <a href="https://en.cppreference.com/w/" target="_blank">cppreference.com</a><br>
                    <em>Very thorough, often not beginner-friendly</em>
                  </li>
                  <li>
                    <a href="https://cplusplus.com/" target="_blank">cplusplus.com</a><br>
                    <em>Also great, beginner-friendly, many examples</em>
                  </li>
                </ol>
                
                <br><br><br><br>
                
                <h2>Book</h2>
                <p><strong>Book:</strong> Dmitrović, S.F (2020). <em>Modern C++ for Absolute Beginners</em></p>
                
              </div>

# CompilerExplorer:
            This example: [godbolt.org/z/6nzE34fKP](https://godbolt.org/z/6nzE34fKP)

# Why _use_ C++?

<br>

<h3>   • Fast/powerful language with predictable resource control</h3>
              <h3>     • "direct"* map to hardware</h3>

<br>

<h3>   • Back-compatible with C and older C++ versions</h3>
              <h3>     • Every* valid C program is a valid C++ program</h3>

<br>
              
              <h3>   • Has a well-defined standard + large standard library </h3>
              <h3>     • (algorithm, numeric etc.)</h3>

<br>
              
              <h3>   • Multi-paradigm (generic, functional, object-oriented, data-o, etc.) </h3>
              <h3>     • High-level language with low-level control</h3>
              <h4>       • Propaganda: <i>"High level language that leaves no room for a lower-level one"</i></h4>
              <h4>       • Propaganda: <i>"Zero-cost abstraction"</i></h4>
              <h3>     • Write nice high-level OO code, same(/better) performance as C or Fortran</h3>

<br>
              
              <h3>   • Directly interface with other languages (C, Fortran etc.) - LAPACK </h3>
              <h3>   • Widely used: many experts, lots of existing programs/libraries etc.</h3>

</div>
            <div style="text-align: center; float: right; width: 20%">
              <br>
              <img src="img/c++.png" style="width: 70%">
            </div>

# Downsides?

### Many of the above also come with drawbacks..

<br>

<h3>   • <b>HUGE</b> language, with many features</h3>
              <h3>     • Can be confusing/overwhelming</h3>
              <h3>     • Many features are rarely used</h3>

<br>

<h3>   • Many old, obsolete features (for back-compatiblity)</h3>
              <h3>     • Can make it difficult to learn, especially from old sources</h3>

<br>

<h3>   • Very powerful: can be easy to shoot yourself in the foot</h3>
              <h3>     • It will happily let you do almost anything.. including very bad ideas [<a href="https://godbolt.org/z/4xG8asb7P">e.g.</a>]
              </h3>

<br>

<h3>   • Quite verobse</h3>
              <h3>     • Often requires more code/typing than other languages</h3>
              <h3>     • This becomes less of an issue with time and for large projects</h3>

<br>

<h3>   • Designed for large-scale projects</h3>
              <h3>     • Can seem overly-combersome for small projects</h3>

</div>
            <div style="text-align: center; float: right; width: 20%">
              <br>
              <img src="img/c++.png" style="width: 70%">
            </div>

# Example: good/bad?

<div style="text-align: left; float: left; width: 40%">
            <div class="sl-block" data-block-type="code" style="width: 40%; height: auto;">
              <div class="sl-block-style">
                <div class="sl-block-content notranslate" data-highlight-theme="ir-black" style="border-style: solid; border-width: 1px;" 
                data-code-frame="none" data-code-autoheight="true">
                <pre class="cpp" style="font-size: 24px; line-height: 32px;"><code style="padding: 20px;" data-line-numbers=""
                >double f(double x, double y) {
                  double a, b, c;
                  a = (4.0 / 3) * M_PI * x * x * x;
                  b = (4.0 / 3) * M_PI * x * y * y;
                  c = a - b;
                  if (c > 0.0) {
                    return c;
                  } else {
                    return -c;
                  }
                }
                </code></pre></div></div></div>
            </div>

<div style="text-align: left; float: right; width: 55%">
              <div class="fragment">
                <h2>Bad!</h2>
              </div>
              <br>
              <div class="fragment">
                <h3>  • Uninitialised variables</h3>
                <h3>    • Hard to follow/debug: common source of error!</h3>
              </div>
              <br>
              <div class="fragment">
                <h3>  • Code transcription; copy/paste errors</h3>
                <h3>    • Extra work, hard to maintain, 2x probability of error</h3>
              </div>
              <br>
              <div class="fragment">
                <h3>  • Unclear naming</h3>
                <h3>    • Confusing, hard to understand</h3>
              </div>
            </div>

# Example: good/bad?

<div style="text-align: left; float: left; width: 50%">
            <div class="sl-block" data-block-type="code" style="width: 50%; height: auto;">
              <div class="sl-block-style">
                <div class="sl-block-content notranslate" data-highlight-theme="ir-black" style="border-style: solid; border-width: 1px;" 
                data-code-frame="none" data-code-autoheight="true">
                <pre class="cpp" style="font-size: 24px; line-height: 32px;"><code style="padding: 20px;" data-line-numbers=""
>double sphere_volume(double radius) {
  return (4.0 / 3) * M_PI * std::pow(radius, 3);
}

double volume_difference(double radius1, double radius2) {
  const double volume1 = sphere_volume(radius1);
  const double volume2 = sphere_volume(radius2);
  return std::abs(volume1 - volume2);
}
                </code></pre></div></div></div>
            </div>

<div style="text-align: left; float: right; width: 45%">
              <div class="fragment">
                <h2>Good</h2>
              <br>
                <h3>  • Variables defined + initialised where used</h3>
              <br>
                <h3>  • Makes use of named functions</h3>
              <br>
                <h3>  • Clear variable naming</h3>
              </div>
            </div>