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<div class="slides">
<section id="title-slide">
<h1 class="title">Laboratorio di TNDS – Lezione 8</h1>
<p class="author">Maurizio Tomasi</p>
<p class="date">Martedì 12 Novembre 2024</p>
</section>
<section id="alcuni-problemi-di-stdvector" class="slide level1">
<h1>Alcuni problemi di <code>std::vector</code></h1>
</section>
<section id="stdvector" class="slide level1">
<h1><code>std::vector</code></h1>
<ul>
<li><p>Finora abbiamo sempre usato <code>std::vector</code> per
memorizzare sequenze di valori, e si potrebbero usare anche
nell’esercitazione di oggi:</p>
<div class="sourceCode" id="cb1"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="kw">struct</span> FunzioneVettorialeBase <span class="op">{</span></span>
<span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a> <span class="kw">virtual</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> Eval<span class="op">(</span><span class="at">const</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> <span class="op">&</span>x<span class="op">)</span> <span class="at">const</span> <span class="op">=</span> <span class="dv">0</span><span class="op">;</span></span>
<span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span>
<span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a><span class="kw">struct</span> OscillatoreArmonico <span class="op">:</span> FunzioneVettorialeBase <span class="op">{</span></span>
<span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> Eval<span class="op">(</span><span class="at">const</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> <span class="op">&</span>x<span class="op">)</span> <span class="at">const</span> <span class="kw">override</span> <span class="op">{</span></span>
<span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a> <span class="cf">return</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">>{</span>x<span class="op">[</span><span class="dv">1</span><span class="op">],</span> <span class="op">-</span>x<span class="op">[</span><span class="dv">0</span><span class="op">]};</span></span>
<span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a> <span class="op">}</span></span>
<span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span></code></pre></div></li>
<li><p>L’uso di <code>std::vector</code> ha però una serie di svantaggi
in questo contesto.</p></li>
</ul>
</section>
<section id="svantaggio-1-velocità" class="slide level1">
<h1>Svantaggio #1: velocità</h1>
<ul>
<li><p>Creare un nuovo oggetto <code>std::vector</code> è un’operazione
<strong>lenta</strong>! Internamente <code>std::vector</code> crea un
puntatore a un array:</p>
<div class="sourceCode" id="cb2"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb2-1"><a href="#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="kw">template</span> <span class="op"><</span><span class="kw">typename</span> T<span class="op">></span></span>
<span id="cb2-2"><a href="#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="kw">class</span> vector <span class="op">{</span></span>
<span id="cb2-3"><a href="#cb2-3" aria-hidden="true" tabindex="-1"></a> T <span class="op">*</span> <span class="va">m_data</span><span class="op">;</span></span>
<span id="cb2-4"><a href="#cb2-4" aria-hidden="true" tabindex="-1"></a> <span class="dt">size_t</span> <span class="va">m_size</span><span class="op">;</span></span>
<span id="cb2-5"><a href="#cb2-5" aria-hidden="true" tabindex="-1"></a><span class="kw">public</span><span class="op">:</span></span>
<span id="cb2-6"><a href="#cb2-6" aria-hidden="true" tabindex="-1"></a> vector<span class="op">(</span><span class="dt">size_t</span> size<span class="op">)</span> <span class="op">:</span> <span class="va">m_size</span><span class="op">{</span>size<span class="op">}</span> <span class="op">{</span> <span class="va">m_data</span> <span class="op">=</span> <span class="kw">new</span> T<span class="op">[</span><span class="va">m_size</span><span class="op">];</span> <span class="op">}</span></span>
<span id="cb2-7"><a href="#cb2-7" aria-hidden="true" tabindex="-1"></a> <span class="op">~</span>vector<span class="op">()</span> <span class="op">{</span> <span class="kw">delete</span><span class="op">[]</span> <span class="va">m_data</span><span class="op">;</span> <span class="op">}</span></span>
<span id="cb2-8"><a href="#cb2-8" aria-hidden="true" tabindex="-1"></a> <span class="dt">size_t</span> size<span class="op">()</span> <span class="at">const</span> <span class="op">{</span> <span class="cf">return</span> <span class="va">m_size</span><span class="op">;</span> <span class="op">}</span></span>
<span id="cb2-9"><a href="#cb2-9" aria-hidden="true" tabindex="-1"></a> <span class="co">// ...</span></span>
<span id="cb2-10"><a href="#cb2-10" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span></code></pre></div></li>
<li><p>Ma <code>new</code> richiede molto lavoro da parte del sistema
operativo, che deve ogni volta individuare un’area di memoria non
occupata da altre variabili.</p></li>
</ul>
</section>
<section id="svantaggio-2-controlli" class="slide level1">
<h1>Svantaggio #2: controlli</h1>
<ul>
<li><p>È impossibile per il compilatore sapere se due variabili
<code>std::vector</code> hanno lo stesso numero di elementi</p></li>
<li><p>Dobbiamo verificare noi a mano che le dimensioni di vettori siano
compatibili:</p>
<div class="sourceCode" id="cb3"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a><span class="kw">template</span> <span class="op"><</span><span class="kw">typename</span> T<span class="op">></span></span>
<span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>vector<span class="op"><</span>T<span class="op">></span> <span class="kw">operator</span><span class="op">+(</span><span class="at">const</span> <span class="bu">std::</span>vector<span class="op"><</span>T<span class="op">></span> <span class="op">&</span>a<span class="op">,</span> <span class="at">const</span> <span class="bu">std::</span>vector<span class="op"><</span>T<span class="op">></span> <span class="op">&</span>b<span class="op">)</span> <span class="op">{</span></span>
<span id="cb3-3"><a href="#cb3-3" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb3-4"><a href="#cb3-4" aria-hidden="true" tabindex="-1"></a> <span class="ot">assert</span><span class="op">(</span>ssize<span class="op">(</span>a<span class="op">)</span> <span class="op">==</span> ssize<span class="op">(</span>b<span class="op">));</span> <span class="co">// Don't forget to do this!</span></span>
<span id="cb3-5"><a href="#cb3-5" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb3-6"><a href="#cb3-6" aria-hidden="true" tabindex="-1"></a> <span class="co">// ...</span></span>
<span id="cb3-7"><a href="#cb3-7" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div></li>
<li><p>Dimenticarsi un <code>assert</code> da qualche parte nel codice
potrebbe avere conseguenze disastrose (soprattutto durante
l’esame!)</p></li>
</ul>
</section>
<section id="svantaggio-3-leggibilità" class="slide level1">
<h1>Svantaggio #3: leggibilità</h1>
<ul>
<li><p>Siccome <code>std::vector</code> può contenere un numero
variabile di elementi, è difficile capire su quante dimensioni lavori
una classe derivata da <code>FunzioneVettorialeBase</code>:</p>
<div class="sourceCode" id="cb4"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a><span class="kw">struct</span> FunzioneVettorialeBase <span class="op">{</span></span>
<span id="cb4-2"><a href="#cb4-2" aria-hidden="true" tabindex="-1"></a> <span class="kw">virtual</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> Eval<span class="op">(</span><span class="at">const</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> <span class="op">&</span>x<span class="op">)</span> <span class="op">=</span> <span class="dv">0</span><span class="op">;</span></span>
<span id="cb4-3"><a href="#cb4-3" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span>
<span id="cb4-4"><a href="#cb4-4" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb4-5"><a href="#cb4-5" aria-hidden="true" tabindex="-1"></a><span class="kw">struct</span> OscillatoreArmonico <span class="op">:</span> FunzioneVettorialeBase <span class="op">{</span></span>
<span id="cb4-6"><a href="#cb4-6" aria-hidden="true" tabindex="-1"></a> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> Eval<span class="op">(</span><span class="at">const</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> <span class="op">&</span>x<span class="op">)</span> <span class="kw">override</span> <span class="op">{</span></span>
<span id="cb4-7"><a href="#cb4-7" aria-hidden="true" tabindex="-1"></a> <span class="co">// Lo spazio delle fasi è a 2 dimensioni, ma questo è chiaro solo</span></span>
<span id="cb4-8"><a href="#cb4-8" aria-hidden="true" tabindex="-1"></a> <span class="co">// se si contano gli elementi del vettore restituito!</span></span>
<span id="cb4-9"><a href="#cb4-9" aria-hidden="true" tabindex="-1"></a> <span class="cf">return</span> vector<span class="op"><</span><span class="dt">double</span><span class="op">>{</span>x<span class="op">[</span><span class="dv">1</span><span class="op">],</span> <span class="op">-</span>x<span class="op">[</span><span class="dv">0</span><span class="op">]};</span></span>
<span id="cb4-10"><a href="#cb4-10" aria-hidden="true" tabindex="-1"></a> <span class="op">}</span></span>
<span id="cb4-11"><a href="#cb4-11" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span></code></pre></div></li>
</ul>
</section>
<section id="uso-di-stdarray" class="slide level1">
<h1>Uso di <code>std::array</code></h1>
</section>
<section id="la-classe-stdarray" class="slide level1">
<h1>La classe <code>std::array</code></h1>
<ul>
<li><p>La libreria standard offre una classe perfetta per gli esercizi
di oggi: <code>std::array</code>.</p></li>
<li><p>Essa è equivalente ad un array con un numero
<strong>fissato</strong> di elementi, che vengono controllati in fase di
compilazione.</p></li>
<li><p>Gli array sono allocati nella memoria <em>stack</em>, che è
velocissima da usare ma limitata. Dovrebbero essere usati solo se il
numero di elementi <strong>non supera qualche decina</strong>.</p></li>
</ul>
</section>
<section id="esempio-di-implementazione" class="slide level1">
<h1>Esempio di implementazione</h1>
<ul>
<li><p>Un’implementazione semplificata di <code>std::array</code> è la
seguente, che <strong>non</strong> usa <code>new</code>:</p>
<div class="sourceCode" id="cb5"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a><span class="kw">template</span> <span class="op"><</span><span class="kw">typename</span> T<span class="op">,</span> <span class="dt">size_t</span> N<span class="op">></span> <span class="co">// I template C++ possono essere usati per tipi</span></span>
<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a><span class="kw">class</span> array <span class="op">{</span> <span class="co">// come `double` e valori come `size_t`</span></span>
<span id="cb5-3"><a href="#cb5-3" aria-hidden="true" tabindex="-1"></a> T <span class="va">m_data</span><span class="op">[</span>N<span class="op">];</span> <span class="co">// Non è un puntatore, ma un array di dimensione nota</span></span>
<span id="cb5-4"><a href="#cb5-4" aria-hidden="true" tabindex="-1"></a><span class="kw">public</span><span class="op">:</span></span>
<span id="cb5-5"><a href="#cb5-5" aria-hidden="true" tabindex="-1"></a> <span class="dt">size_t</span> size<span class="op">()</span> <span class="at">const</span> <span class="op">{</span> <span class="cf">return</span> N<span class="op">;</span> <span class="op">}</span> <span class="co">// Ritorna il valore costante N</span></span>
<span id="cb5-6"><a href="#cb5-6" aria-hidden="true" tabindex="-1"></a> <span class="co">// ...</span></span>
<span id="cb5-7"><a href="#cb5-7" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span></code></pre></div></li>
<li><p>Se il valore <code>N</code> è ridotto a pochi elementi (due o
tre), il compilatore può addirittura decidere di evitare di usare lo
<em>stack</em> ed impiega invece i <em>registri</em> (che è il tipo di
memoria usabile dalla CPU più veloce in assoluto)</p></li>
</ul>
</section>
<section class="slide level1">
<ul>
<li><p>Finora abbiamo sempre visto <code>typename T</code> nei template,
dicendo che il tipo (<code>double</code>, <code>float</code>,
<code>int</code>…) deve essere fornito quando si <em>istanzia</em> il
template:</p>
<div class="sourceCode" id="cb6"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a><span class="kw">template</span> <span class="op"><</span><span class="kw">typename</span> T<span class="op">></span> <span class="kw">class</span> Vettore <span class="op">{</span> T <span class="op">*</span> arr<span class="op">;</span> <span class="co">/* ... */</span> <span class="op">};</span></span>
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a>Vettore<span class="op"><</span><span class="dt">double</span><span class="op">></span> v<span class="op">;</span> <span class="co">// Vettore di double</span></span>
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a>Vettore<span class="op"><</span><span class="dt">int</span><span class="op">></span> w<span class="op">;</span> <span class="co">// Vettore di interi</span></span></code></pre></div></li>
<li><p>Usare <code>size_t N</code> indica che nella definizione di
<code>std::array</code>, il valore numerico di <code>N</code> è un
intero senza segno da fornire quando si istanzia il template:</p>
<div class="sourceCode" id="cb7"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb7-1"><a href="#cb7-1" aria-hidden="true" tabindex="-1"></a><span class="kw">template</span> <span class="op"><</span><span class="dt">size_t</span> N<span class="op">></span> <span class="kw">class</span> Array <span class="op">{</span> <span class="dt">double</span> arr<span class="op">[</span>N<span class="op">];</span> <span class="co">/* ... */</span> <span class="op">};</span></span>
<span id="cb7-2"><a href="#cb7-2" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb7-3"><a href="#cb7-3" aria-hidden="true" tabindex="-1"></a>Array<span class="op"><</span><span class="dv">3</span><span class="op">></span> v<span class="op">;</span> <span class="co">// Array di 3 elementi</span></span>
<span id="cb7-4"><a href="#cb7-4" aria-hidden="true" tabindex="-1"></a>Array<span class="op"><</span><span class="dv">4</span><span class="op">></span> w<span class="op">;</span> <span class="co">// Array di 4 elementi</span></span></code></pre></div></li>
</ul>
</section>
<section id="uso-di-stdarray-1" class="slide level1">
<h1>Uso di <code>std::array</code></h1>
<ul>
<li><p>Quando si istanzia <code>std::array</code>, bisogna specificare
anche la dimensione:</p>
<div class="sourceCode" id="cb8"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb8-1"><a href="#cb8-1" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>vector<span class="op"><</span><span class="dt">double</span><span class="op">></span> v<span class="op">(</span><span class="dv">2</span><span class="op">);</span> <span class="co">// The size is 2, but it can change later</span></span>
<span id="cb8-2"><a href="#cb8-2" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array<span class="op"><</span><span class="dt">double</span><span class="op">,</span> <span class="dv">2</span><span class="op">></span> a<span class="op">;</span> <span class="co">// The size is 2 and *cannot* change</span></span>
<span id="cb8-3"><a href="#cb8-3" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb8-4"><a href="#cb8-4" aria-hidden="true" tabindex="-1"></a>v<span class="op">[</span><span class="dv">0</span><span class="op">]</span> <span class="op">=</span> <span class="fl">0.5</span><span class="op">;</span> v<span class="op">.</span>at<span class="op">(</span><span class="dv">1</span><span class="op">)</span> <span class="op">=</span> <span class="fl">1.0</span><span class="op">;</span> <span class="co">// Both std::vector and std::array can be</span></span>
<span id="cb8-5"><a href="#cb8-5" aria-hidden="true" tabindex="-1"></a>a<span class="op">[</span><span class="dv">0</span><span class="op">]</span> <span class="op">=</span> <span class="fl">0.7</span><span class="op">;</span> a<span class="op">.</span>at<span class="op">(</span><span class="dv">1</span><span class="op">)</span> <span class="op">=</span> <span class="fl">2.0</span><span class="op">;</span> <span class="co">// accessed using [] or .at()</span></span>
<span id="cb8-6"><a href="#cb8-6" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb8-7"><a href="#cb8-7" aria-hidden="true" tabindex="-1"></a>v<span class="op">.</span>push_back<span class="op">(</span><span class="fl">3.14159</span><span class="op">);</span> <span class="co">// Ok, the array will grow</span></span>
<span id="cb8-8"><a href="#cb8-8" aria-hidden="true" tabindex="-1"></a>a<span class="op">.</span>push_back<span class="op">(</span><span class="fl">2.71828</span><span class="op">);</span> <span class="co">// ERROR, you cannot use push_back with an array</span></span></code></pre></div></li>
<li><p>Si può inizializzare un array in maniera immediata:</p>
<div class="sourceCode" id="cb9"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb9-1"><a href="#cb9-1" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array<span class="op"><</span><span class="dt">double</span><span class="op">,</span> <span class="dv">4</span><span class="op">></span> a<span class="op">{</span><span class="fl">1.0</span><span class="op">,</span> <span class="fl">2.0</span><span class="op">,</span> <span class="fl">3.0</span><span class="op">,</span> <span class="fl">4.0</span><span class="op">};</span> <span class="co">// Ok, but if you use -std=c++23…</span></span>
<span id="cb9-2"><a href="#cb9-2" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array a<span class="op">{</span><span class="fl">1.0</span><span class="op">,</span> <span class="fl">2.0</span><span class="op">,</span> <span class="fl">3.0</span><span class="op">,</span> <span class="fl">4.0</span><span class="op">};</span> <span class="co">// …"double" and "4" are redundant!</span></span></code></pre></div></li>
</ul>
</section>
<section id="uso-negli-esercizi" class="slide level1">
<h1>Uso negli esercizi</h1>
<ul>
<li><p>L’anno scorso ho proposto agli alunni più volonterosi di usare
<code>std::array</code>, per questi motivi:</p>
<ol type="1">
<li><p>Il codice è circa 10 volte più veloce, e questo è importante
soprattutto se si devono fare Monte Carlo di problemi con equazioni
differenziali;</p></li>
<li><p>In sede di esame vediamo a volte errori di dimensionalità, che
<code>std::array</code> previene;</p></li>
<li><p>Non è necessario implementare controlli sulla dimensione degli
array, perché ci pensa il compilatore.</p></li>
</ol></li>
<li><p>Questo è il primo anno in cui ho aggiornato la pagina <a
href="carminati-esercizi-08.html">carminati-esercizi-08.html</a> perché
usi <code>std::array</code>!</p></li>
</ul>
</section>
<section id="controlli" class="slide level1">
<h1>Controlli</h1>
<ul>
<li><p>Se combino due array con lunghezza diversa</p>
<div class="sourceCode" id="cb10"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array x<span class="op">{</span><span class="fl">1.0</span><span class="op">,</span> <span class="fl">2.0</span><span class="op">};</span> <span class="co">// An array with 2 elements</span></span>
<span id="cb10-2"><a href="#cb10-2" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array y<span class="op">{</span><span class="fl">3.0</span><span class="op">,</span> <span class="fl">4.0</span><span class="op">,</span> <span class="fl">5.0</span><span class="op">};</span> <span class="co">// An array with 3 elements</span></span>
<span id="cb10-3"><a href="#cb10-3" aria-hidden="true" tabindex="-1"></a><span class="bu">std::</span>array z<span class="op">{</span>x <span class="op">+</span> y<span class="op">};</span> <span class="co">// Gosh, what's going to happen?</span></span></code></pre></div>
<p>il compilatore <code>g++</code> produce un errore di
compilazione:</p>
<pre><code>test_arr.cpp:64:13: error: no match for ‘operator+’ (operand types are ‘std::array<double, 2>’ and ‘std::array<double, 3>’)
64 | array z{x + y};
| ~ ^ ~
| | |
| | array<[...],3>
| array<[...],2></code></pre></li>
<li><p>Nel caso di <code>std::vector</code>, il codice compilerebbe ma
andrebbe poi in crash.</p></li>
</ul>
</section>
<section id="leggibilità" class="slide level1">
<h1>Leggibilità</h1>
<ul>
<li><p>Con tutte le dimensioni esplicitate, il codice diventa più
leggibile</p></li>
<li><p>Ad esempio, nel derivare la classe
<code>OscillatoreArmonico</code> dell’<a
href="carminati-esercizi-08.html#esercizio-8.1">esercizio 8.1</a>
bisogna specificare <code><2></code> per
<code>FunzioneVettorialeBase</code>:</p>
<div class="sourceCode" id="cb12"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb12-1"><a href="#cb12-1" aria-hidden="true" tabindex="-1"></a><span class="kw">struct</span> OscillatoreArmonico <span class="op">:</span> FunzioneVettorialeBase<span class="op"><</span><span class="dv">2</span><span class="op">></span> <span class="op">{</span></span>
<span id="cb12-2"><a href="#cb12-2" aria-hidden="true" tabindex="-1"></a> <span class="co">// ...</span></span>
<span id="cb12-3"><a href="#cb12-3" aria-hidden="true" tabindex="-1"></a><span class="op">};</span></span></code></pre></div></li>
<li><p>Similmente, nel <code>main</code> dello stesso si definisce
l’istanza di <code>Eulero</code> così:</p>
<div class="sourceCode" id="cb13"><pre
class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb13-1"><a href="#cb13-1" aria-hidden="true" tabindex="-1"></a>Eulero<span class="op"><</span><span class="dv">2</span><span class="op">></span> myEuler<span class="op">;</span> <span class="co">// Metodo di Eulero per un'equazione di secondo grado</span></span></code></pre></div></li>
</ul>
</section>
<section id="seminario-di-fine-semestre" class="slide level1">
<h1>Seminario di fine semestre</h1>
</section>
<section id="seminario-su-c-python-e-julia" class="slide level1">
<h1>Seminario su C++, Python e Julia</h1>
<ul>
<li><p>Negli scorsi anni ho proposto un seminario di approfondimento su
C++, Assembler, Python e Julia, una volta terminata la sessione di esami
di Febbraio.</p></li>
<li><p>Nel seminario spiego le differenze tra di loro, mostro come sono
progettati i rispettivi compilatori, e do indicazioni su come scegliere
lo strumento di lavoro migliore.</p></li>
<li><p>Se siete interessati, compilate il Google Form all’indirizzo <a
href="https://forms.gle/saJjERRmYR6KxPpe9"
class="uri">https://forms.gle/saJjERRmYR6KxPpe9</a>: alla fine del
semestre contatterò chi l’ha compilato per decidere la data migliore per
tutti.</p></li>
</ul>
</section>
</div>
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