Trouble logging uint8 message fields

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#include <ros/ros.h>
#include "turtlesim/Color.h"
#include <iomanip>
void apple(const turtlesim::Color& msg)
{
    ROS_INFO_STREAM(std::setprecision ( 0 )
<< " color=(" << msg.r << " , " << msg.b << " , " << msg.g << " ) ");
    }
    int main(int argc, char **argv)
    {
        ros::init(argc, argv, "pose_subscriber");
        ros::NodeHandle n;
        ros::Subscriber pose_sub = n.subscribe("/turtle1/color_sensor", 10, &apple);
    ros::spin();
    return 0;
}

why do my output so strange? my output is like a lot of this:

[ INFO] [1582904454.849200284]:  color=(E , ? , V )

can someone tell me where do i did wrong?thanks very much!