Completed Turtlesim sine challenge

src/challenge/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.5)
+project(challenge)
+
+# Default to C99
+if(NOT CMAKE_C_STANDARD)
+  set(CMAKE_C_STANDARD 99)
+endif()
+
+# Default to C++14
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 14)
+endif()
+
+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(geometry_msgs REQUIRED)
+find_package(turtlesim REQUIRED)
+
+if(BUILD_TESTING)
+  find_package(ament_lint_auto REQUIRED)
+  ament_lint_auto_find_test_dependencies()
+endif()
+
+add_executable(solution src/solution.cpp)
+ament_target_dependencies(solution rclcpp geometry_msgs turtlesim)
+
+install(TARGETS
+  solution
+  DESTINATION lib/${PROJECT_NAME})
+
+ament_package()
+

src/challenge/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>challenge</name>
+  <version>0.0.0</version>
+  <description>TODO: Package description</description>
+  <maintainer email="warrenlukedmello@gmail.com">warren2005</maintainer>
+  <license>TODO: License declaration</license>
+
+  <buildtool_depend>ament_cmake</buildtool_depend>
+
+  <depend>rclcpp</depend>
+  <depend>geometry_msgs</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/challenge/src/solution.cpp

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+#include <chrono>
+#include <cmath>
+#include "rclcpp/rclcpp.hpp"
+#include "turtlesim/msg/pose.hpp"
+#include "turtlesim/srv/teleport_absolute.hpp"
+#include "geometry_msgs/msg/twist.hpp"
+
+using namespace std::chrono_literals;
+
+class SinePlotter : public rclcpp::Node
+{
+public:
+    SinePlotter() : Node("solution_node"), t_(0.0)
+    {
+        client_ = this->create_client<turtlesim::srv::TeleportAbsolute>("/turtle1/teleport_absolute");
+
+        // wait for teleport service
+        while(!client_->wait_for_service(1s)) {
+            RCLCPP_INFO(this->get_logger(), "Waiting for turtlesim...");
+        }
+
+        timer_ = this->create_wall_timer(20ms, std::bind(&SinePlotter::plot_callback, this));
+    }
+
+private:
+    void plot_callback()
+    {
+        double x0 = 5.5;   // center of screen (midpoint)
+        double y0 = 5.5;   // vertical starting point
+        double amplitude = 3.0; // height of sine wave
+        double speed = 0.05;    // how fast to move across x-axis
+        double frequency = 2.0; // sine wave frequency
+
+        double x = x0 + t_;
+        double y = y0 + amplitude * std::sin(frequency * t_);
+        double theta = 0.0; // orientation doesn't matter
+
+        auto request = std::make_shared<turtlesim::srv::TeleportAbsolute::Request>();
+        request->x = x;
+        request->y = y;
+        request->theta = theta;
+        client_->async_send_request(request);
+
+        t_ += speed;
+    }
+
+    rclcpp::TimerBase::SharedPtr timer_;
+    rclcpp::Client<turtlesim::srv::TeleportAbsolute>::SharedPtr client_;
+    double t_;
+};
+
+int main(int argc, char * argv[])
+{
+    rclcpp::init(argc, argv);
+    rclcpp::spin(std::make_shared<SinePlotter>());
+    rclcpp::shutdown();
+    return 0;
+}
+