My program slows down while operating with a loop in pointcloud

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Hi everyone. So I'm in the process of writing my own library for pointcloud . Now I'm stuck on a path. I have a function that I'm currently designing to give out x,y, and z values of the points in pointcould and then publish the same pointcloud after the iteration of the current pointcloud is over. But because there is a loop inside the function because of which the rate at which the pointcloud is published after its iteration is slowed down..Could you please find me a way to increase the published rate of the pointcloud than you? thanks in advance ..

        int i;
        sensor_msgs::PointCloud2 dummy;
        sensor_msgs::PointCloud2 &outputpass =dummy;
        outputpass=cloud_msg;
        for ( sensor_msgs::PointCloud2ConstIterator<float> it(outputpass,  "x"); it != it.end(); ++it) 
          {     
          cout <<" POINT CLOUD :"<< endl;
          cout<<" "<<endl;
          cout << "z " << it[2] << '\n'; 
          i++;
          }

pubpass.publish(outputpass);