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asked 2016-08-02 23:19:56 -0500

SaurabhR gravatar image

updated 2016-08-02 23:20:26 -0500

Hi, Can somebody explain me the following line of code line by line ? The code has been taken from ros tutorials.

  std_msgs::String msg;
  std::stringstream ss;
 ss << "hello world " << count; = ss.str();

Here is the link to the code

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answered 2016-08-03 01:38:33 -0500

Horse-man gravatar image

updated 2016-08-03 01:41:15 -0500

It will simply create a ROS message, fill it with a text and print it. Here's the line by line explanation:

std_msgs::String msg;  // create a standard message object of type String (used to send messages between ROS services / nodes / programs)

std::stringstream ss;  // create a stringstream object which will store our text and take care of other operations on strings 

ss << "hello world " << count;  // fill the stringsream object with text "Hello world X". X represent the iteration number which was previously stored in "count" variable = ss.str();  // fill the data field of our ROS message with the text we previously stored in the stringstream object (you can see the stringstream object as a buffer where we store text) 

ROS_INFO("%s",; // print the content of the ROS message in the console and save it in the log file
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Asked: 2016-08-02 23:19:56 -0500

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Last updated: Aug 03 '16