[Bug] Gradebot Error

[mcankizilkaya]

This is an error report.

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Screenshot of the error

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Error details

I wrote my code correctly but I still receive error on gradebot.

[bayodesegun]

@mcankizilkaya
You have not given us much to work with here.

• What’s the message from gradebot?
• When the gradebot fails your submission, it states several things you can check. Did you check them? Can you tell us the result of each check?

[mcankizilkaya]

This is mycode:

#include "geometry_msgs/msg/twist.hpp"
#include "rclcpp/rclcpp.hpp"
#include "sensor_msgs/msg/laser_scan.hpp"
#include <chrono>

using namespace std::chrono_literals;
using std::placeholders::_1;

class MoveRobot : public rclcpp::Node {
public:
  MoveRobot() : Node("move_robot") {
    publisher_ =
        this->create_publisher<geometry_msgs::msg::Twist>("cmd_vel", 10);
    subscription_ = this->create_subscription<sensor_msgs::msg::LaserScan>(
        "/scan", 10, std::bind(&MoveRobot::topic_callback, this, _1));
  }

private:
  void topic_callback(const sensor_msgs::msg::LaserScan::SharedPtr msg) {
    auto message = geometry_msgs::msg::Twist();
    message.linear.x = 0.0;
    message.angular.z = 0.0;
    if (msg->ranges[359] < 1.0) {
      message.angular.z = 0.4;

    } else {
      message.linear.x = 0.4;
      for (int i = 370; i < 720; i++) {
        if (msg->ranges[i] < 1.0) {
          message.linear.x = 0.0;
          message.angular.z = 0.4;
        }
      }
    }

    publisher_->publish(message);
  }
  rclcpp::TimerBase::SharedPtr timer_;
  rclcpp::Publisher<geometry_msgs::msg::Twist>::SharedPtr publisher_;
  rclcpp::Subscription<sensor_msgs::msg::LaserScan>::SharedPtr subscription_;
};

int main(int argc, char *argv[]) {
  rclcpp::init(argc, argv);
  rclcpp::spin(std::make_shared<MoveRobot>());
  rclcpp::shutdown();
  return 0;
}

And this is the error that Gradebot gives me:

[Album] imgur.com

[bayodesegun]

@bayodesegun

Can you tell us the result of each check?

What is the result of your check of each of the points the gradebot raised? That’s the key to this problem.

[neilthomas110]

Your node should be named topics_quiz_node

class MoveRobot : public rclcpp::Node {
public:
  MoveRobot() : Node("topics_quiz_node") {
//instead of "move_robot"