From db87dfcf1c10b0f926a933bfd84c41358d5d256a Mon Sep 17 00:00:00 2001
From: Michael Mandl <mandlm@molez.net>
Date: Sat, 4 Nov 2023 18:20:13 +0100
Subject: [PATCH] feat: variadic templates

---
 chapters/chapter_02/CMakeLists.txt            |  3 +-
 .../chapter_02/include/variadic_templates.h   | 10 ++++++
 .../chapter_02/src/variadic_templates.cpp     | 36 +++++++++++++++++++
 src/main.cpp                                  |  2 ++
 4 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 chapters/chapter_02/include/variadic_templates.h
 create mode 100644 chapters/chapter_02/src/variadic_templates.cpp

diff --git a/chapters/chapter_02/CMakeLists.txt b/chapters/chapter_02/CMakeLists.txt
index f656efe..5972957 100644
--- a/chapters/chapter_02/CMakeLists.txt
+++ b/chapters/chapter_02/CMakeLists.txt
@@ -7,7 +7,8 @@ add_library(
   src/null.cpp
   src/range_based_for.cpp
   src/structured_binding.cpp
-  src/type_inference.cpp)
+  src/type_inference.cpp
+  src/variadic_templates.cpp)
 
 target_compile_features(chapter_02 PUBLIC cxx_std_20)
 
diff --git a/chapters/chapter_02/include/variadic_templates.h b/chapters/chapter_02/include/variadic_templates.h
new file mode 100644
index 0000000..7ecac63
--- /dev/null
+++ b/chapters/chapter_02/include/variadic_templates.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "chapter_interface.h"
+
+class VariadicTemplates : public ChapterTest {
+  virtual void run() override;
+  virtual const char *name() const override {
+    return "Variadic templates test";
+  }
+};
diff --git a/chapters/chapter_02/src/variadic_templates.cpp b/chapters/chapter_02/src/variadic_templates.cpp
new file mode 100644
index 0000000..140b818
--- /dev/null
+++ b/chapters/chapter_02/src/variadic_templates.cpp
@@ -0,0 +1,36 @@
+#include "variadic_templates.h"
+#include <iostream>
+
+template <typename T> void my_recursive_printf(T value) {
+  std::cout << value << std::endl;
+}
+
+template <typename T, typename... Ts>
+void my_recursive_printf(T value, Ts... args) {
+  std::cout << value;
+  my_recursive_printf(args...);
+}
+
+template <typename T, typename... Ts>
+void my_expanded_printf(T value, Ts... args) {
+  std::cout << value;
+
+  if constexpr (sizeof...(args) > 0) {
+    my_expanded_printf(args...);
+  } else {
+    std::cout << std::endl;
+  }
+}
+
+template <typename... T> auto sum(T... t) { return (t + ...); }
+
+void VariadicTemplates::run() {
+  std::cout << "my_recursive_printf(1, 2, \"3\", 4.5, \"hello\"): ";
+  my_recursive_printf(1, 2, "3", 4.5, "hello");
+
+  std::cout << "my_expanded_printf(1, 2, \"3\", 4.5, \"hello\"): ";
+  my_expanded_printf(1, 2, "3", 4.5, "hello");
+
+  std::cout << "sum(1, 2, 3, 4, 5, 6, 7): " << sum(1, 2, 3, 4, 5, 6, 7)
+            << std::endl;
+}
diff --git a/src/main.cpp b/src/main.cpp
index ee52b78..07fcc69 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -11,6 +11,7 @@
 #include "range_based_for.h"
 #include "structured_binding.h"
 #include "type_inference.h"
+#include "variadic_templates.h"
 #include "version.h"
 
 int main(int argc, char **argv) {
@@ -28,6 +29,7 @@ int main(int argc, char **argv) {
   chapter_2_tests.emplace_back(std::make_unique<TypeInferenceTest>());
   chapter_2_tests.emplace_back(std::make_unique<IfConstexprTest>());
   chapter_2_tests.emplace_back(std::make_unique<RangeBasedForTest>());
+  chapter_2_tests.emplace_back(std::make_unique<VariadicTemplates>());
 
   for (auto &test : chapter_2_tests) {
     std::cout << "\n" << test->name() << ":" << std::endl;