RSS chose XML instead of JSON because: 1) XML's structure and verification capabilities are better than JSON, which is suitable for the needs of RSS complex data structures; 2) XML was supported extensively at that time; 3) Early versions of RSS were based on XML and have become a standard.

RSS is an XML-based format used to publish and subscribe to content. The XML structure of an RSS file includes a root element, an element, and multiple elements, each representing a content entry. Read and parse RSS files through XML parser, and users can subscribe and get the latest content.

RSS documents are a simple subscription mechanism to publish content updates through XML files. 1. The RSS document structure consists of and elements and contains multiple elements. 2. Use RSS readers to subscribe to the channel and extract information by parsing XML. 3. Advanced usage includes filtering and sorting using the feedparser library. 4. Common errors include XML parsing and encoding issues. XML format and encoding need to be verified during debugging. 5. Performance optimization suggestions include cache RSS documents and asynchronous parsing.

XML has the advantages of structured data, scalability, cross-platform compatibility and parsing verification in RSS. 1) Structured data ensures consistency and reliability of content; 2) Scalability allows the addition of custom tags to suit content needs; 3) Cross-platform compatibility makes it work seamlessly on different devices; 4) Analytical and verification tools ensure the quality and integrity of the feed.

You can use the TinyXML, Pugixml, or libxml2 libraries to process XML data in C. 1) Parse XML files: Use DOM or SAX methods, DOM is suitable for small files, and SAX is suitable for large files. 2) Generate XML file: convert the data structure into XML format and write to the file. Through these steps, XML data can be effectively managed and manipulated.

RSS and XML are still important in the modern web. 1.RSS is used to publish and distribute content, and users can subscribe and get updates through the RSS reader. 2. XML is a markup language and supports data storage and exchange, and RSS files are based on XML.

Working with XML data structures in C can use the TinyXML or pugixml library. 1) Use the pugixml library to parse and generate XML files. 2) Handle complex nested XML elements, such as book information. 3) Optimize XML processing code, and it is recommended to use efficient libraries and streaming parsing. Through these steps, XML data can be processed efficiently.

RSS enables multimedia content embedding, conditional subscription, and performance and security optimization. 1) Embed multimedia content such as audio and video through tags. 2) Use XML namespace to implement conditional subscriptions, allowing subscribers to filter content based on specific conditions. 3) Optimize the performance and security of RSSFeed through CDATA section and XMLSchema to ensure stability and compliance with standards.