taming-cpp

commit 0b43d984905f07c59e3236d98d4e27409aba3cda
parent d0f3f64bb42ea8194c20f0eadd35821cab346143
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Fri, 17 Jan 2025 16:23:24 +0100

More stuff with templates

Diffstat:
A
templates/factorial.cpp
 | 
22
++++++++++++++++++++++
A
templates/println.cpp
 | 
18
++++++++++++++++++
A
templates/std_array.cpp
 | 
16
++++++++++++++++

3 files changed, 56 insertions(+), 0 deletions(-)
diff --git a/templates/factorial.cpp 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
@@ -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
@@ -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;
+}