Write a block in PL/SQL to display the name of department and their head

DECLARE
    CURSOR emp_dep_cur  IS
      SELECT department_name,
             manager_id
      FROM   departments;
    emp_manager employees.first_name%TYPE;
	
BEGIN
dbms_output.Put_line(Rpad('Department', 30)||Rpad('Department Head', 30));
dbms_output.Put_line('----------------------------------------------');
    FOR emp_dep_rec  IN emp_dep_cur LOOP
        IF emp_dep_rec.manager_id IS NULL THEN
          emp_manager := 'yet to join';
        ELSE
          SELECT first_name
          INTO   emp_manager
          FROM   employees
          WHERE  employee_id = emp_dep_rec.manager_id;
        END IF;

        dbms_output.Put_line(Rpad(emp_dep_rec.department_name, 30)
                             || emp_manager);
    END LOOP;
END;
/

Sample Output:

SQL> /
Department                    Department Head
----------------------------------------------
Administration                Jennifer
Marketing                     Michael
Purchasing                    Den
Human Resources               Susan
Shipping                      Adam
IT                            Alexander
Public Relations              Hermann
Sales                         John
Executive                     Steven
Finance                       Nancy
Accounting                    Shelley
Treasury                      yet to join
Corporate Tax                 yet to join
Control And Credit            yet to join
Shareholder Services          yet to join
Benefits                      yet to join
Manufacturing                 yet to join
Construction                  yet to join
Contracting                   yet to join
Operations                    yet to join
IT Support                    yet to join
NOC                           yet to join
IT Helpdesk                   yet to join
Government Sales              yet to join
Retail Sales                  yet to join
Recruiting                    yet to join
Payroll                       yet to join

PL/SQL procedure successfully completed.