Improve basic slides

bernhardmgruber · sponce · commit d312100ae221 · 2023-03-06T21:01:08.000+01:00
diff --git a/talk/basicconcepts/arrayspointers.tex b/talk/basicconcepts/arrayspointers.tex
@@ -73,16 +73,19 @@
   \begin{block}{A pointer to nothing}
     \begin{itemize}
     \item if a pointer doesn't point to anything, set it to \cppinline{nullptr}
+    \begin{itemize}
+      \item useful to e.g.\ mark the end of a linked data structure
+      \item or absence of an optional function argument (pointer)
+    \end{itemize}
     \item same as setting it to 0 or \cppinline{NULL} (before \cpp11)
     \item triggers compilation error when assigned to integer
     \end{itemize}
   \end{block}
   \pause
   \begin{exampleblock}{Example code}
     \begin{cppcode*}{}
-      void* vp = nullptr;
       int* ip = nullptr;
-      int i = NULL;      // OK -> bug?
+      int i = NULL;      // compiles, bug?
       int i = nullptr;   // ERROR
     \end{cppcode*}
   \end{exampleblock}
diff --git a/talk/basicconcepts/auto.tex b/talk/basicconcepts/auto.tex
@@ -10,7 +10,7 @@
     \end{itemize}
     \begin{cppcode*}{}
       std::vector<int> v;
-      int a = v[3];
+      float a = v[3];    // conversion intended?
       int b = v.size();  // bug? unsigned to signed
     \end{cppcode*}
   \end{block}
@@ -19,7 +19,7 @@
     \begin{cppcode*}{}
       std::vector<int> v;
       auto a = v[3];
-      const auto b = v.size();
+      const auto b = v.size(); // std::size_t
       int sum{0};
       for (auto n : v) { sum += n; }
     \end{cppcode*}
diff --git a/talk/basicconcepts/classenum.tex b/talk/basicconcepts/classenum.tex
@@ -86,9 +86,11 @@
     \vfill \null
   \end{multicols}
   \onslide<7->{
-  \begin{exampleblock}{}
-    Starting with \cpp17: prefer \cppinline{std::variant}
-  \end{exampleblock}
+  \begin{goodpractice}{Avoid unions}
+    \begin{itemize}
+      \item Starting with \cpp17: prefer \cppinline{std::variant}
+    \end{itemize}
+  \end{goodpractice}
   }
 \end{frame}
 
diff --git a/talk/basicconcepts/control.tex b/talk/basicconcepts/control.tex
@@ -56,13 +56,16 @@
   \pause
   \begin{exampleblock}{Practical example}
     \begin{cppcode*}{}
-      int collatz(int a) {
-        return a==1 ? 1 : collatz(a%2==0 ? a/2 : 3*a+1);
-      }
+      const int charge = isLepton ? -1 : 0;
     \end{cppcode*}
   \end{exampleblock}
   \pause
   \begin{alertblock}{Do not abuse it}
+    \begin{cppcode*}{}
+      int collatz(int a) {
+        return a==1 ? 1 : collatz(a%2==0 ? a/2 : 3*a+1);
+      }
+    \end{cppcode*}
     \begin{itemize}
       \item Explicit \cppinline{if}s are generally easier to read
       \item Use the ternary operator with short conditions and expressions
@@ -103,17 +106,17 @@
       enum class Lang { French, German, English, Other };
       Lang language = ...;
       switch (language) {
-      case Lang::French:
-        std::cout << "Bonjour";
-        break;
-       case Lang::German:
-        std::cout << "Guten Tag";
-        break;
-      case Lang::English:
-        std::cout << "Good morning";
-        break;
-      default:
-        std::cout << "I do not speak your language";
+        case Lang::French:
+          std::cout << "Bonjour";
+          break;
+        case Lang::German:
+          std::cout << "Guten Tag";
+          break;
+        case Lang::English:
+          std::cout << "Good morning";
+          break;
+        default:
+          std::cout << "I do not speak your language";
       }
     \end{cppcode*}
   \end{exampleblock}
@@ -144,17 +147,16 @@
 
 \begin{frame}[fragile]
   \frametitlecpp[17]{Init-statements for if and switch}
-  \begin{block}{}
+  \begin{block}{Purpose}
     Allows to limit variable scope in \cppinline{if} and \cppinline{switch} statements
   \end{block}
   \begin{exampleblock}{\cpp17}
     \begin{cppcode*}{}
       if (Value val = GetValue(); condition(val)) {
-        f(val);
-      } else {
-        g(val);
-      }
-      h(val); // compile error
+        f(val); // ok
+      } else
+        g(val); // ok
+      h(val);   // error, no `val` in scope here
     \end{cppcode*}
   \end{exampleblock}
   \pause
@@ -224,7 +226,7 @@
 
 \begin{frame}[fragile]
   \frametitlecpp[20]{Init-statements for range-based loops}
-  \begin{block}{}
+  \begin{block}{Purpose}
     Allows to limit variable scope in range-based loops
   \end{block}
   \begin{alertblock}{\cpp17}
@@ -252,6 +254,7 @@
       while(condition) {
         statements;
       }
+
       do {
         statements;
       } while(condition);
diff --git a/talk/basicconcepts/operators.tex b/talk/basicconcepts/operators.tex
@@ -2,7 +2,7 @@
 
 \begin{frame}[fragile]
   \frametitlecpp[98]{Operators(1)}
-  \begin{block}{Binary \& Assignment Operators}
+  \begin{block}{Binary and Assignment Operators}
     \begin{cppcode*}{}
       int i = 1 + 4 - 2;  // 3
       i *= 3;             // 9, short for: i = i * 3;
@@ -11,7 +11,7 @@
     \end{cppcode*}
   \end{block}
   \pause
-  \begin{block}{Increment / Decrement \uncover<3->{\hfill \alert{\bf Use wisely}}}
+  \begin{block}{Increment / Decrement Operators \uncover<3->{\hfill \alert{\bf Use wisely}}}
     \begin{cppcode*}{}
       int i = 0; i++; // i = 1
       int j = ++i;    // i = 2, j = 2
@@ -35,7 +35,7 @@
     \end{cppcode*}
   \end{block}
   \pause
-  \begin{block}{Boolean Operators}
+  \begin{block}{Logical Operators}
     \begin{cppcode*}{}
       bool a = true;
       bool b = false;
diff --git a/talk/basicconcepts/references.tex b/talk/basicconcepts/references.tex
@@ -7,7 +7,6 @@
       \item References allow for direct access to another object
       \item They can be used as shortcuts / better readability
       \item They can be declared \cppinline{const} to allow only read access
-      \item They can be used as function arguments
     \end{itemize}
   \end{block}
 
@@ -21,6 +20,7 @@
       struct A { int x; int y; } a;
       const int &x = a.x; // direct read access to A's x
       x = 4;              // doesn't compile
+      a.x = 4;            // fine
     \end{cppcode*}
   \end{exampleblock}
 \end{frame}
