Merge pull request #19 from gjbex/development

Development

source-code/Algorithms/CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required(VERSION 3.0)
+project(algorithms LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMaKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_EXTENSIONS NO)
+
+add_compile_options(-Wall -Wextra -Wpedantic)
+
+add_executable(find_if.exe
+    find_if.cpp)
+add_executable(permutations.exe
+    permutations.cpp)
+add_executable(generate.exe
+    generate.cpp)
+add_executable(for_each.exe
+    for_each.cpp)
+add_executable(particle_sort.exe
+    particle_sort.cpp)
+add_executable(count_clamp.exe
+    count_clamp.cpp)
+add_executable(find_words.exe
+    find_words.cpp)
+add_executable(zip_it.exe
+    zip_it.cpp)
+add_executable(accumulate.exe
+    accumulate.cpp)
+add_executable(distance.exe
+    distance.cpp)
+add_executable(iota.exe
+    iota.cpp)
+add_executable(transform.exe
+    transform.cpp)
+add_executable(points.exe
+    points.cpp)

source-code/Algorithms/README.md

@@ -25,4 +25,5 @@ Code illustrations for chapter 10, Algorithms in Stroustrup's
 1. `distances.cpp`: illustrating a `std::back_inserter` in an
     `std::transform`.
 1. `iota.cpp`: initialize a `valarray` using `iota` and apply a function.
-1. `Makefile`: make file to build the code.
+1. `points.cpp`: illustration of using C++20's spaceship operator.
+1. `CMakeLists.txt`: CMake file to build the code.

source-code/Algorithms/points.cpp

@@ -0,0 +1,29 @@
+#include <algorithm>
+#include <compare>
+#include <iostream>
+#include <vector>
+
+struct Point {
+    double x, y;
+    int id;
+    auto operator<=>(const Point&) const = default;    
+    friend std::ostream& operator <<(std::ostream& out, const Point& p);
+};
+
+std::ostream& operator <<(std::ostream& out, const Point& p) {
+    return out << p.id << ": (" << p.x << ", " << p.y << ")";
+}
+
+int main() {
+    std::vector<Point> points;
+    points.emplace_back(4.1, 5.2, 1);
+    points.emplace_back(2.1, 7.2, 2);
+    points.emplace_back(1.2, 9.2, 3);
+    points.emplace_back(2.1, 3.2, 4);
+    points.emplace_back(2.1, 3.2, 5);
+    std::sort(points.begin(), points.end());
+    for (const auto& point: points) {
+        std::cout << point << "\n";
+    }
+    return 0;
+}