To assign float numbers to double arrays

edit

As @bob-ROS mentioned, is there a reason you need to use a double[7]? If you instead used another std::vector<double> this would be a trivial operation.

@jarvisschultz the problem is I am rather new to c++ and don't know what options I have. On the other hand , I'm also new to ros_control to know what's possible. Can you please also note how you would write it? especially how I should declare it in the header file.

Maybe something like this

#include <vector>
std::vector<double> joint_position_;
// then you should be able to do something like this:
joint_position_ = j_state_srv.response.j_state.position

@jarvisschultz It gave another error. In some other lines I also use them like the below. I'm not sure if ros_control is compatible with it.

for (int i = 0; i < num_joints_; ++i) {
     hardware_interface::JointStateHandle    jointStateHandle (
                                                            joint_names_    [i],
                                            &joint_position_ [i],
                                &joint_velocity_ [i],
                                    &joint_effort_     [i]);
        // Create position joint interface
        hardware_interface::JointHandle    jointPositionHandle (jointStateHandle, &joint_position_command_[i]);
        hardware_interface::JointHandle    jointVelocityHandle (jointStateHandle, &joint_velocity_command_[i]);
        hardware_interface::JointHandle    jointEffortHandle   (jointStateHandle, &joint_effort_command_  [i]);}