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//--------------------------------------------------------------------------

//                           Dynamic Casting

//                           www.24x7fpga.com

//--------------------------------------------------------------------------

// Parent class

class parent_class;

   // class properties or variables

  int a, b, s;

​

   // task method

  task func ( );                 

    s = a + b;

    disp();

  endtask

  function void disp( );                 

    $display("Parent Class => a = %0d , b = %0d, sum s = %0d", a, b, s);

  endfunction

​

​

endclass

​

// Child Class

class child_class extends parent_class;

  // class properties or variables

  int m;

  // task method

  task func ( );

    m = a * b;

    disp();

  endtask

  function void disp( );

    $display("Child Class  => a = %0d , b = %0d, mul m = %0d", a, b, m);

  endfunction

endclass

​

module tb_dynamic_cast;

  parent_class pr_obj;          // declare a handle for parent class

  child_class cl_obj;           // declare a handle for child class

  child_class cl_obj_2;         // declare another handle for child class

   initial begin 

     cl_obj = new( );           // construct an object

     pr_obj = cl_obj;           

     $cast(cl_obj_2, pr_obj);   // DYNAMIC CASTING

                                // parent class assigned to child class

     pr_obj.a = 20;             

     cl_obj.b = 15;

     $display("------------ Dynamic Casting ------------");

     cl_obj_2.func();           // access a method 

   end

​

endmodule