I want to read an array of integers from a file and publish them on a topic

edit

#

 ros::Publisher publisher = nh.advertise<std_msgs::Int32MultiArray>("Topic_1",1);

  std_msgs::Int32MultiArray vec;

  int i=0;

  ifstream infile("array1.txt");
  while(infile >> temp)
    {
      vec[i++] = temp;
      // publisher.publish(temp);
    }
  publisher.publish(vec);

1. > #but I'm getting this error after I run the command $catkin_make in my > workspace

#

 ...
    [ 85%] [ 92%] [100%] Built target subscriber
    Building CXX object task/CMakeFiles/publisher_1.dir/src/publisher_1.cpp.o
    Building CXX object task/CMakeFiles/publisher_2.dir/src/publisher_2.cpp.o
    /home/kv/krssg/src/task/src/publisher_1.cpp: In function ‘int main(int, char**)’:
    /home/kv/krssg/src/task/src/publisher_1.cpp:27:10: error: no match for ‘operator[]’ (operand types are ‘std_msgs::Int32MultiArray’ and ‘int’)
           vec[i++] = temp;
              ^
    /home/kv/krssg/src/task/src/publisher_2.cpp: In function ‘int main(int, char**)’:
    /home/kv/krssg/src/task/src/publisher_2.cpp:25:11: error: no match for ‘operator[]’ (operand types are ‘std_msgs::Int32MultiArray’ and ‘int’)
           vec2[i++] = temp;
               ^
    make[2]: *** [task/CMakeFiles/publisher_1.dir/src/publisher_1.cpp.o] Error 1
    make[1]: *** [task/CMakeFiles/publisher_1.dir/all] Error 2
    make[1]: *** Waiting for unfinished jobs....
    make[2]: *** [task/CMakeFiles/publisher_2.dir/src/publisher_2.cpp.o] Error 1
    make[1]: *** [task/CMakeFiles/publisher_2.dir/all] Error 2
    make: *** [all] Error 2
    Invoking "make -j4 -l4" failed