feat(hw1): First iteration of pubsub random number

src/hw1_pubsub/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.8)
+project(hw1_pubsub)
+
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+# find dependencies
+find_package(ament_cmake REQUIRED)
+find_package(rclcpp REQUIRED)
+find_package(std_msgs REQUIRED)
+# uncomment the following section in order to fill in
+# further dependencies manually.
+# find_package(<dependency> REQUIRED)
+
+add_executable(1_pub src/1-publisher.cpp)
+add_executable(2_sub src/2-subscriber.cpp)
+
+ament_target_dependencies(1_pub rclcpp std_msgs)
+ament_target_dependencies(2_sub rclcpp std_msgs)
+
+install (
+  TARGETS
+    1_pub
+    2_sub
+  DESTINATION lib/${PROJECT_NAME}
+)
+
+if(BUILD_TESTING)
+  find_package(ament_lint_auto REQUIRED)
+  # the following line skips the linter which checks for copyrights
+  # comment the line when a copyright and license is added to all source files
+  set(ament_cmake_copyright_FOUND TRUE)
+  # the following line skips cpplint (only works in a git repo)
+  # comment the line when this package is in a git repo and when
+  # a copyright and license is added to all source files
+  set(ament_cmake_cpplint_FOUND TRUE)
+  ament_lint_auto_find_test_dependencies()
+endif()
+
+ament_package()

src/hw1_pubsub/package.xml

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+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>hw1_pubsub</name>
+  <version>0.0.0</version>
+  <description>TODO: Package description</description>
+  <maintainer email="wessel@todo.todo">wessel</maintainer>
+  <license>TODO: License declaration</license>
+
+  <buildtool_depend>ament_cmake</buildtool_depend>
+
+  <test_depend>ament_lint_auto</test_depend>
+  <test_depend>ament_lint_common</test_depend>
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>

src/hw1_pubsub/src/1-publisher.cpp

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+/* hw1_pubsub/1-publisher.cpp
+ * Node that publishes a random integer every 3 seconds.
+ *
+ * Reviewed by: <x>
+ * Changelog:
+ * [04-09-2025] Wessel T: Implement template
+ * [09-09-2025] Wessel T: (BASE) Work out assignment
+ */
+
+#include <cstdlib>
+
+#include "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/int32.hpp" // For random integer publisher
+
+class NodeHw1RandomPublisher : public rclcpp::Node {
+
+public:
+  NodeHw1RandomPublisher()
+		: Node("node_hw1_random_publisher")
+  {
+		publisher_random_number_ =
+			this->create_publisher<std_msgs::msg::Int32>("random_number", 10);
+
+		timer_random_number_ = this->create_wall_timer(
+			std::chrono::seconds(3),
+			std::bind(&NodeHw1RandomPublisher::timer_random_number_function, this)
+		);
+  }
+
+  void timer_random_number_function() {
+	  std_msgs::msg::Int32 msg;
+	  msg.data = std::rand() % 101;
+	  publisher_random_number_->publish(msg);
+	
+    RCLCPP_INFO(this->get_logger(), "Published random number: %d", msg.data);
+  }
+
+private:
+	rclcpp::Publisher<std_msgs::msg::Int32>::SharedPtr publisher_random_number_;
+	rclcpp::TimerBase::SharedPtr timer_random_number_;
+};
+
+int main(int argc,char *argv[]) {
+  rclcpp::init(argc,argv);
+
+  auto node = std::make_shared<NodeHw1RandomPublisher>();
+  rclcpp::spin(node);
+  rclcpp::shutdown();
+
+  return 0;
+}

src/hw1_pubsub/src/2-subscriber.cpp

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+
+/* hw1_pubsub/2-subscriber.cpp
+ * Node that subscribes and expect a random integer. Adds 1000 to it.
+ *
+ * Reviewed by: <x>
+ * Changelog:
+ * [04-09-2025] Wessel T: Implement template
+ * [09-09-2025] Wessel T: (BASE) Work out assignment
+ */
+
+#include <cstdlib>
+
+#include "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/int32.hpp" // For random integer publisher
+
+using namespace std::placeholders;
+
+class NodeHw1RandomSubscriber : public rclcpp::Node {
+
+public:
+  NodeHw1RandomSubscriber()
+    : Node("node_hw1_random_subscriber")
+  {
+    subscriber_random_number_ =
+      this->create_subscription<std_msgs::msg::Int32>(
+        "random_number", 10,
+        std::bind(&NodeHw1RandomSubscriber::callback_random_number, this, _1)
+      );
+  }
+
+  void callback_random_number(const std_msgs::msg::Int32::SharedPtr msg) {
+    int result = msg->data + 1000;
+  
+    RCLCPP_INFO(this->get_logger(), 
+      "Received: %d, after adding 1000: %d", msg->data, result
+    );
+  }
+
+private:
+  rclcpp::Subscription<std_msgs::msg::Int32>::SharedPtr subscriber_random_number_;
+};
+
+int main(int argc,char *argv[]) {
+  rclcpp::init(argc,argv);
+
+  auto node = std::make_shared<NodeHw1RandomSubscriber>();
+  rclcpp::spin(node);
+  rclcpp::shutdown();
+
+  return 0;
+}