Separate names with a comma.
Difference between link exchange and link building
Actually link building is more wide determination, than link exchange.
You can find more here: https://seo-hacker.com/link-building-tutorial-link-exchange/
The term link exchange is included in link building, that are techniques that you use to build a system that link back to your money site
Link building (alternative spellings include linkbuilding and link-building) refers to the process of getting external pages to link to a page on your website. It is one of the many tactics used in search engine optimization (SEO).
Isn't link exchange just 2 websites who decide to put each other's backlinks to benefit both of them?
as the name suggests a link exchange is giving a link to another website in exchange for your link on that website. and link building is getting backlinks to your website from some high authority websites.
Link building = the process of acquiring hyperlinks from other websites to your own. A hyperlink (usually just called a link) is a way for users to navigate between pages on the internet (MOZ)
A link exchange = a confederation of websites that operates similarly to a web ring. Webmasters register their web sites with a central organization, that runs the exchange, and in turn receive from the exchange HTML code which they insert into their web pages (Wikipedia)
Link exchange is exchanging backlinks between two or more mutual websites. Link building is the process of building one way links without providing a backlink.
I think that the difference is only in the method of obtaining links.