Can I use an extend class in function with an arguments?

SystemVerilog
,
5

In reply to chris_le:

Hi,
The original code is like this.

class A ; 
   function void disp (); 
    $display(" Non-Virtual from A "); 
  endfunction
  virtual function void vdisp (); 
    $display(" Virtual from A "); 
  endfunction
endclass 
 
class EA extends A ;
   function void disp (); 
    $display(" Non-Virtual from EA "); 
  endfunction
  virtual function void vdisp (); 
    $display(" Virtual from EA "); 
  endfunction
endclass 
 
module main ; 
  function void disp( A a);
    a.disp();
    a.vdisp();
  endfunction
 
  A my_a; 
  EA my_ea;
  initial 
    begin 
      my_a = new(); 
      my_ea = new(); 
 
      disp(my_a); 
      disp(my_ea); 
 
    end 
endmodule

Would you let me know why do we have to have virtual to all functions?
Actually, the original example isn’t assigned virtual in non-virtual function as you can see the above code.

So I’ve got the below results,

Non-Virtual from A
Virtual from A
Non-Virtual from A
Virtual from EA

I think this example is how vitual work in Systemverilog. But I didn’t get it, do we need vitual keyword for all function?