Minor code changes

lectures/code/test.cpp

@@ -0,0 +1,25 @@
+class Image {
+ public:
+  static inline int instance_counter{};
+
+  Image() { instance_counter++; }
+  Image(const Image&) { instance_counter++; }
+  Image(Image&&) = default;
+  Image& operator=(const Image&) = default;
+  Image& operator=(Image&&) = default;
+  ~Image() { instance_counter--; }
+};
+
+#include <iostream>
+
+int main() {
+  std::cout << "Current count: " << Image::instance_counter << std::endl;
+  Image image;
+  std::cout << "Current count: " << Image::instance_counter << std::endl;
+  {
+    Image image_copy{image};
+    std::cout << "Current count: " << Image::instance_counter << std::endl;
+  }
+  std::cout << "Current count: " << Image::instance_counter << std::endl;
+  return 0;
+}

lectures/static_in_classes.md

@@ -128,13 +128,14 @@ class Foo {
 ```
 <!--
 `CPP_SETUP_START`
-#include "foo.hpp"
 $PLACEHOLDER
 `CPP_SETUP_END`
 `CPP_COPY_SNIPPET` weird_calling/main.cpp
 `CPP_RUN_CMD` CWD:weird_calling c++ -std=c++17 -c main.cpp
 -->
 ```cpp
+#include "foo.hpp"
+
 int main() {
   Foo::PublicStaticFunction();
   Foo foo;