Upcasting and narrow casting in oo-abap

Question

hi friends,
please tell me clearly about the Up casting and Down casting with examples in OO-ABAP.
thanks and regards.
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Edited by: Vinod Kumar on Nov 9, 2011 5:32 PM

Answer 1

Hi,
     Instance components exist separately in each instance (object) of the class and are referred using instance component selector using u2018u2019.
     Static components can be used without even creating an instance of the class and are referred to using static component selector     u2018 =>u2019 .
CLASS c1 DEFINITION.
PUBLIC SECTION.
  data : i_num type i value 5.
  class-data :   
    s_num type i value 6 .
ENDCLASS.
CLASS c1 IMPLEMENTATION.
ENDCLASS.
START-OF-SELECTION.
DATA : oref1 TYPE REF TO c1 .
CREATE OBJECT : oref1.
write:/5 oref1->i_num.
write:/5 c1=>s_num .
write:/5 oref1->s_num.
                         Instance, self-referenced, and static methods can all be called dynamically; the class name for static methods can also be determined dynamically:
u2022     oref->(method)
u2022     me->(method)
u2022     class=>(method)
u2022     (class)=>method
u2022     (class)=>(method)