ROS C++ - Ⅰ
================

Comparing C and C++ Programming Rules
^^^^^^^^^^^^^^^^

- C and C++ are related programming languages, with C++ being an extension of C. While they share many concepts and syntax elements, C++ introduces additional features and paradigms, such as object-oriented programming (OOP). Here are some key differences:

Object-Oriented Programming (OOP):

    C++ supports OOP with features like classes, objects, inheritance, and polymorphism, allowing for more organized and modular code.
    C does not directly support OOP; it relies on procedural programming.

Classes and Objects:

    C++ allows the creation of classes to encapsulate data and methods into objects.
    C does not have classes or built-in support for objects.

Standard Template Library (STL):

    C++ provides the STL, which includes ready-to-use containers (like vectors, maps, and queues) and algorithms.
    C does not have a built-in STL.

Namespaces:

    C++ has namespaces to avoid naming conflicts and provide better organization of code.
    C does not have namespaces.

Function Overloading:

    C++ supports function overloading, which allows multiple functions with the same name but different parameter lists.
    C does not support function overloading.

Type Safety:

    C++ offers stronger type safety through features like the static_cast operator and type-safe template classes.
    C has fewer type safety features.

Creating a ROS C++ Package
^^^^^^^^^^^^^^^^

- To create a ROS package using C++, follow these steps:

    - Open a terminal and navigate to your ROS workspace directory.

    - Create a new ROS package using the catkin_create_pkg command, specifying the package name and any dependencies. Include roscpp as a dependency for C++ programming:

        .. code-block:: bash

            catkin_create_pkg my_cpp_package roscpp rospy std_msgs
            
    - Navigate to the package directory:

        .. code-block:: bash

            cd my_cpp_package

    - Create a src directory to store your C++ source code:
        
        .. code-block:: bash

            mkdir src

    - Inside the src directory, you can start writing your C++ nodes using ROS APIs and C++ programming.

ROS C++ Build Settings
^^^^^^^^^^^^^^^^

- ROS uses Catkin as its build system. Here's how to configure your ROS C++ package's build settings:

    - Open the CMakeLists.txt file located in your package directory.

    - Add the following lines to find the required ROS packages and set the compiler flags:

        .. code-block:: cmake

            find_package(catkin REQUIRED COMPONENTS
                roscpp
                rospy
                std_msgs
            )

            catkin_package()

            include_directories(
                ${catkin_INCLUDE_DIRS}
            )

    - For each C++ node you create, add an executable target in your CMakeLists.txt:

        .. code-block:: cmake

            add_executable(my_cpp_node src/my_cpp_node.cpp)
            target_link_libraries(my_cpp_node ${catkin_LIBRARIES})

    - Build your package using the following commands:

        .. code-block:: bash
            
            catkin_make

    - This command compiles your package's code and generates the necessary executables and libraries.

    - Creating a ROS C++ package involves configuring CMake for your project, creating C++ nodes using ROS APIs, and using catkin_make to build your code.

    - If your projects become more complex, you might need to handle additional dependencies, custom messages, and more sophisticated build configurations.