Cursor for loop in Oracle

declare
  l_sql varchar2(123);        -- variable that contains a query
  l_c   sys_refcursor;        -- cursor variable(weak cursor).
  l_res your_table%rowtype;   -- variable containing fetching data
begin
  l_sql := 'select * from your_table';

  -- Open the cursor and fetching data explicitly
  -- in the LOOP.

  open l_c for l_sql;

  loop
    fetch l_c into l_res;
    exit when l_c%notfound;   -- Exit the loop if there is nothing to fetch.
     -- process fetched data 

  end loop;

  close l_c; -- close the cursor
end;