构造方法

REPORT  Z_METHOD_CONSTRUCTOR.
CLASS vehicle DEFINITION.
  PUBLIC SECTION.
    METHODS: accelerate IMPORTING rate type i,
      constructor IMPORTING i_speed TYPE i,  构造方法的定义必须使用关键字  constructor
        show_speed.

  PRIVATE SECTION.
    data speed TYPE i VALUE 0.
ENDCLASS.

CLASS vehicle IMPLEMENTATION.
  method accelerate.
    speed = speed + rate.
  ENDMETHOD.

  METHOD show_speed.
    write speed.
  ENDMETHOD.

  METHOD constructor.
    speed = i_speed.
  ENDMETHOD.
ENDCLASS.

DATA o_vehicle TYPE REF TO vehicle.

START-OF-SELECTION.
CREATE OBJECT o_vehicle EXPORTING i_speed = 4.   "构造方法只能在第一次创建对象中直接被调用，只调用一次
CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
CALL METHOD o_vehicle->show_speed.