// Load the configuration file Ogre::ConfigFile configFile; configFile.load("ogre.cfg"); // Access the "RenderSystem" section Ogre::ConfigFile::SettingsMultiMap& settings = configFile.getSection("RenderSystem"); // Iterate through all settings in the section Ogre::ConfigFile::SettingsMultiMap::iterator it; for (it = settings.begin(); it != settings.end(); ++it) { Ogre::String key = it->first; Ogre::String value = it->second; // Do something with the key-value pair, e.g. set a render option renderSystem->setOption(key, value); }In this example, we first load the "ogre.cfg" configuration file and then access the "RenderSystem" section using the getSection method. We then iterate through each key-value pair in the section using the SettingsMultiMap.begin() method, and extract the key and value strings using the iterator's ->first and ->second members, respectively. Finally, we can use the retrieved key-value pairs to set various rendering options using the Ogre::RenderSystem API. The package library for the Ogre graphics engine is typically installed using package managers such as apt-get on Linux systems, or using precompiled binary releases on Windows systems. The library files and headers can also be manually downloaded and compiled from the official Ogre GitHub repository.