Caching is saving the contents of a web page for quick retrieval at a specific time, usually so the same page doesn't have to be processed over and over again. Indexing just goes through a web page, fetches the imporotant information and stores it (like google?). Well at least that's how I understand it.
When Search Engine Bot Comes to your website tat means Crawling, After Crawle your webpage Search Engine bot get a copy in his database that's call indexing. You can see index data on your screen that's call Cache of your website.
chaching and indexing are work as algorithems.In chaching crawler only crawl our page content.
And in indexing crawler crawl page content and this data are store in database.In short indexing
collects, parses, and stores data and in caching collect and parse data.