From 0b43d984905f07c59e3236d98d4e27409aba3cda Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Fri, 17 Jan 2025 16:23:24 +0100
Subject: More stuff with templates

---
 templates/factorial.cpp | 22 ++++++++++++++++++++++
 templates/println.cpp   | 18 ++++++++++++++++++
 templates/std_array.cpp | 16 ++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 templates/factorial.cpp
 create mode 100644 templates/println.cpp
 create mode 100644 templates/std_array.cpp

(limited to 'templates')

diff --git a/templates/factorial.cpp b/templates/factorial.cpp
new file mode 100644
index 0000000..11e4789
--- /dev/null
+++ b/templates/factorial.cpp
@@ -0,0 +1,22 @@
+// Taken from https://en.wikipedia.org/wiki/Template_metaprogramming
+
+#include <iostream>
+
+template<long long N>
+class factorial {
+public:
+	static constexpr long long value = N * factorial<N-1>::value;
+};
+
+template<>
+class factorial<0> {
+public:
+	static constexpr long long value = 1;
+};
+
+int main() {
+	constexpr long long X = 12;
+	std::cout << factorial<X>::value << std::endl;
+
+	return 0;
+}
diff --git a/templates/println.cpp b/templates/println.cpp
new file mode 100644
index 0000000..62f27ac
--- /dev/null
+++ b/templates/println.cpp
@@ -0,0 +1,18 @@
+#include <iostream>
+
+template<auto X> void println() { std::cout << X << std::endl; }
+
+int main() {
+	println<1.23>();
+	println<42>();
+
+	// The following attempts to print a string do not work
+	// uncomment to see why
+	// 1.
+	// println<"Hello!">();
+	// 2.
+	// constexpr std::string_view hello = "Hello!";
+	// println<hello>();
+
+	return 0;
+}
diff --git a/templates/std_array.cpp b/templates/std_array.cpp
new file mode 100644
index 0000000..8044cb2
--- /dev/null
+++ b/templates/std_array.cpp
@@ -0,0 +1,16 @@
+#include <array>
+#include <iostream>
+
+int main() {
+	std::array<double, 5> a {1.0, 1.1, 1.2};
+	std::cout << "Capacity of a: " << a.size() << std::endl;
+
+	a[3] = 1.3;
+	a[4] = 1.4;
+
+	for (auto x : a)
+		std::cout << x << " ";
+	std::cout << std::endl;
+
+	return 0;
+}
-- 
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