how can i save rostopic in array?

edit

Hi guys. I need help.

I want to make nodes that 'subscribe topic - save in array' and 'read array - publish topic'. (in my case it is geometry_msgs::Pointstamped) But there are no references and questions. Is it impossible?? If it`s possible. Could i get some advice or any reference link?

Thanks for reading :)

This is first node. : subscribe clicked_point and save in array. (not perfect yet. i`m still making.)

#include "ros/ros.h"
#include "geometry_msgs/Pointstamped.h"

int waypointList[10];

int i = 0;

void waypointCallback(const geometry_msgs::Pointstamped::ConstPtr& clicked_point)

int main(int argc, char **argv)
{

    ros::init(argc, argv, "waypoint_saver");
    ros::NodeHandle n;

    //subscriber
    ros::Subscriber waypoint_sub = n.subscribe("waypoint", 1, waypointCallback);

    ros::Rate loop_rate(10);

    while (ros::ok())
    {
        //waypoint_pub.header.stamp = ros::Time::now();

        if (i < 10){}
            waypointList[i]=clicked_point;
            i += 1;
        }
        else{        
            ROS_INFO("Full waypoint(10 waypoints) %s")
            return 0
        }
        ros::spinOnce();
        loop_rate.sleep();
    }


  return 0