Assign variable

hi all
what is the difference using this and no using this keyword when assign the variable in the class?

thanks

class A
  int x;
  int y;
  function xx();
    x = 10;
  endfunction
  function yy();
    this.y = 1000;
  endfunction

endclass

In reply to peter:

Please use code tags making your code easier to read. I have added them for you.

https://verificationacademy.com/forums/systemverilog/using-class#reply-64409