SQL Server Cursor Example

I know SQL cursors exist, but I am not sure how or why to use them. Can you provide a SQL cursor example? Can you give any guidance on when to use a SQL Server cursor?

Strange Code

Re-OPENing a Cursor

CLOSEing a cursor

SQL Server Cursor Example

In my T-SQL code I always use set based operations. I have been told these types of operations are what SQL Server is designed to process and it should be quicker than serial processing. I know cursors exist but I am not sure how to use them..