写在前面

自己的测试环境：
Ubuntu20.04
ROS-Noetic

一、问题描述

编译程序时出现如下报错：

-- Could NOT find roscpp (missing: roscpp_DIR)
-- Could not find the required component 'roscpp'. The following CMake error indicates that you either need to install the package with the same name or change your environment so that it can be found.
CMake Error at /opt/ros/noetic/share/catkin/cmake/catkinConfig.cmake:83 (find_package):
  Could not find a package configuration file provided by "roscpp" with any
  of the following names:

    roscppConfig.cmake
    roscpp-config.cmake

  Add the installation prefix of "roscpp" to CMAKE_PREFIX_PATH or set
  "roscpp_DIR" to a directory containing one of the above files.  If "roscpp"
  provides a separate development package or SDK, be sure it has been
  installed.

二、解决方法

首先，确保自己已经安装了 ros-noetic-roscpp

sudo apt-get install ros-noetic-roscpp

然后再次编译，看看是否能够解决问题。
如果还是出现同样的报错，可以在 CMakeLists.txt 中添加如下语句：

set(roscpp_DIR "/opt/ros/noetic/share/roscpp/cmake/")

然后再次编译，再次编译，应该能够解决问题。

参考链接

[1] kimi.