what is the difference between site_url() and base_url()?

Question

As I have read in some resources, base_url() and site_url() functions in codeigniter are almost the same, although my version of code

Answer 1

base_url() that is commonly used in Codeigniter can be used even without the .php extension.

site_url() which is commonly used in Wordpress custom template can be used even when you just call the post_title of the blog or the file name with the extension.