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Now we'll be creating the cpp

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publisher you know already what is the
publisher its a topic on which the data

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will be publishing okay come on to the screen
and here is the method how to create a publisher

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using the C plus plus okay it is saying that
here using this link you can download the code

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okay we have already created the package inside the
already uh C plus plus file present and what we

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will do we have to keep our new code in this SRC
folder in order to maintain a package structure

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click right open in terminal and then you can
just paste the link and these file is downloaded

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so we also want this package to be opened
in the vs code click right here code space

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and here we have let's learn more about
this code so we will just remove that these

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two libraries that will allow us to handle
the memory and uh like using the number so

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these two libraries are related to the uh
ros2 RCL CPP is a ros client library with

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C plus plus and here it is the string that we
string message that we are going to use in our

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publisher you can also use the chatgpt to
get the full explanation of the code here we

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have the namespace and here is the class minimal  publisher that is here from the RCL CPP : : and the node

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here is the function  minimal publisher which is custructor here we are mentioning the node name you can
even change this name here we have the variable

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that is initialized with the zero and here we are
creating a publisher that is publishing messages

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of string type and the topic name is topic and here
we have a timer and it will be repeating itself

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after 500 millisecond node is pointing towards
a minimal publisher and here we have the timer

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callback that is declared in the private here is
the definition of the timer callback here we have

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the message of type string and the message
dot data so it has an instance data in it so

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we are assigning it the string value like a
hello word we're also converting the integer

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to the string in order to add the string here
we have the RCL CPP info it will be printing the

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information on the terminal then it publishes
the message onto the publisher here we have the three

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private member  Declaration the timer and the
publisher and the variable count and the main

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it initializes and then creates the instance
of minimal publisher Class feed into the spin

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function it will be like circling and processing
ros messages and data until it will be shut down

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in order to run this node we will need to
make some changes in package dot XML and

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the cmake list so here we have the method
to add the dependencies in the package.xml

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file so open up here the package.xml so
we have seen two dependencies in the code

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first one is the RCL CPP and the second one is
the STD message so we will be declaring inside

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the package dot XML we will just copy and we
will add these lines after the ament cmake

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we will come here and hit enter and Ctrl
V so we have added these two dependencies

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in our package.xml alright now
it will come to the C make list

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all right here we have already the executable
file that was created when we created the

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package and now we will just copy and go to
here and here we have the find package line

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find package RCL CPP and STD messages
so these are the dependents that we are

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mentioning here now we have to declare our
node so here is the method as executable

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and there there we are mentioning the name of the
node talker and then the related C plus plus file

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ament target dependencies talker depends upon the
RCL CPP and STD messages simply copy this and go

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to here paste it here alright so we are giving
it the name talker okay now we have to mention

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the name of the node inside the install Target so
that draws to run can find the executable okay so

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uh here is the node that we have to mention inside
the install so uh here is the line install we will

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just hit enter there is already an executable
file present so we will just enter and talker

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all right so we have mentioned our node so now we
have told our package that there is a C plus plus

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file and the node name is talker and we have
mentioned the dependencies in package XML file

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we will try to build it open the terminal
go to your ros2 workspace colcon

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build minus minus sym link minus installed

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so it successfully built now we will Source
our local setup install local setup.bash

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so if we have source to first base
now we will write ros2 run

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package name which is turtlesimbot and if we double tab

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it will show us all the executable files
that are available so we will issues topic

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alright so it is publishing now
hello world and the number next to it

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let's modify this publisher we want a
list in which there are several string

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members we will be calling each line one
by one now I will create a list my list

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so we will have to declare the
type we will use the static

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and then std
double colon vector and inside std

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double colon string

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and then space my list

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okay so here we have declared our list and
now we have to mention that how we are going

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to call the member of the list so if we come
here message dot data we are giving the value

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call my list my list and then the member so
so we can use the remainder method so count

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and percentage and then the
size of my list my list dot size

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let's try to build this

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now we'll run our node talker

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uh it is saying I'm learning growth I haven't
made a mistake that this count variable is not

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being increased so previously it was increasing
build it again to node yeah I am learning raw

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through and I will learn micros and I will
make my first row a hardware Robot Turtle

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Sim oh yes so this is how we can modify any
code let's make it even more good looking

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yes and here now we can see that a string
is ending and now it is like printing it

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here so what we will do open up an other
terminal see the ros2 topic list

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here is the topic name uh topic so we
will try to echo it Ros2 topic echo

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and topic name

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and here we can see it is printing all the

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information here as it was
printing it here