DECLARE
   CURSOR c1  IS
   SELECT  col1,col2      FROM mytable;
   n  c1%ROWTYPE;
   
   pcnt   number;
   tot_rc number := 0;
   a number:=1;
  
BEGIN
   pcnt := 0;
   FOR n IN c1 LOOP
      tot_rc  := tot_rc +1;
   end loop;
   
  
   FOR n IN c1 LOOP
     
      pcnt :=round((a*100/tot_rc),0);
      set_application_property (cursor_style, 'BUSY');
      <font color='RED'>
     gt(n.rn);      -- doing calcuation here
 </font>
    
     set_application_property (cursor_style, 'DEFAULT');
     set_item_property('cbk.display_item1',width,pcnt*2);
           
     SYNCHRONIZE;
     a:=a+1;
      
   END LOOP;
     
   END;

<font color='RED'>
     gt(n.rn);      -- doing calcuation here
 </font>