From d0f3f64bb42ea8194c20f0eadd35821cab346143 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Fri, 17 Jan 2025 07:52:02 +0100
Subject: Started work on templates article

---
 README.md          |  9 +++++++++
 templates/pair.cpp | 35 +++++++++++++++++++++++++++++++++++
 templates/swap.cpp | 16 ++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 templates/pair.cpp
 create mode 100644 templates/swap.cpp

diff --git a/README.md b/README.md
index 41825cc..46a15bf 100644
--- a/README.md
+++ b/README.md
@@ -27,3 +27,12 @@ For the
 [second post in the series](https://sebastiano.tronto.net/blog/2024-12-26-taming-cpp-raii/).
 
 Various small examples on constructors, destructors and related things.
+
+## Templates
+
+For the
+[third post](https://sebastiano.tronto.net/blog/2025-01-TODO)
+
+Various examples on templates, constraints and concepts.
+
+See also [zmodn](https://git.tronto.net/zmodn).
diff --git a/templates/pair.cpp b/templates/pair.cpp
new file mode 100644
index 0000000..42b97c9
--- /dev/null
+++ b/templates/pair.cpp
@@ -0,0 +1,35 @@
+#include <iostream>
+
+template <typename S, typename T>
+class Pair {
+public:
+	S first;
+	T second;
+
+	Pair(S s, T t) : first{s}, second{t} {}
+
+	void print() const {
+		std::cout << "(" << first << ", " << second << ")";
+	}
+};
+
+int main() {
+	Pair<int, char> p(42, 'x');
+	p.second = 'y';
+
+	std::cout << "p =";
+	p.print();
+	std::cout << std::endl;
+
+	Pair q(1.23, 7); // template argument deduction
+
+	std::cout << "q =";
+	q.print();
+	std::cout << std::endl;
+
+	std::cout << "int type name: " << typeid(7).name() << std::endl;
+	std::cout << "char type name: " << typeid('x').name() << std::endl;
+	std::cout << "double type name: " << typeid(1.23).name() << std::endl;
+	std::cout << "Type of p: " << typeid(p).name() << std::endl;
+	std::cout << "Type of q: " << typeid(q).name() << std::endl;
+}
diff --git a/templates/swap.cpp b/templates/swap.cpp
new file mode 100644
index 0000000..94e231e
--- /dev/null
+++ b/templates/swap.cpp
@@ -0,0 +1,16 @@
+#include <iostream>
+
+template<typename S, typename T>
+void swap(S& a, T& b) {
+	S tmp = a;
+	a = b;
+	b = tmp;
+}
+
+int main() {
+	int x = 3;
+	std::string y = "1.0";
+	swap(x, y);
+	std::cout << "x: " << x << std::endl;
+	std::cout << "y: " << y << std::endl;
+}
-- 
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