方法參數(shù)傳遞:?
REPORT z_mehtod_para.
*---------------------------------------------------------------------*
*??????? CLASS vehicle DEFINITION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
CLASS vehicle DEFINITION.
?? PUBLIC SECTION.
???? METHODS: accelerate IMPORTING rate TYPE i,
????????????? show_speed.
?? PRIVATE SECTION.
???? DATA speed TYPE i VALUE 0.
ENDCLASS.
*---------------------------------------------------------------------*
*??????? CLASS vehicle IMPLEMENTATION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
CLASS vehicle IMPLEMENTATION.
?? METHOD accelerate.
???? speed = speed + rate.
?? ENDMETHOD.
?? METHOD show_speed.
???? WRITE: / 'Speed:',speed.
?? ENDMETHOD.
ENDCLASS.

DATA o_vehicle TYPE REF TO vehicle.

START-OF-SELECTION.
?? CREATE OBJECT o_vehicle.
?? CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
?? CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
?? CALL METHOD o_vehicle->show_speed.
該示例輸出如下:?
???? 4
方法還可以進(jìn)行動(dòng)態(tài)調(diào)用,即通過變量對(duì)方法進(jìn)行指定,例如下列語句
?? meth = acclerate.
?? call method o_vehicle->(meth).

函數(shù)方法:?
REPORT z_funtional_method.

*---------------------------------------------------------------------*
*??????? CLASS circle DEFINITION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
CLASS circle DEFINITION.
?? PUBLIC SECTION.
???? METHODS get_area IMPORTING value(i_radius) TYPE i
????????????????????? RETURNING value(r_size)??? TYPE f.
?? PRIVATE SECTION.
???? CONSTANTS pi TYPE f VALUE '3.14159265'.
ENDCLASS.
*---------------------------------------------------------------------*
*??????? CLASS circle IMPLEMENTATION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
CLASS circle IMPLEMENTATION.
?? METHOD get_area.
???? r_size = i_radius ** 2 * pi.
?? ENDMETHOD.
ENDCLASS.

PARAMETERS radius TYPE i.
DATA: o_circle TYPE REF TO circle,
?????? area TYPE f.

START-OF-SELECTION.
?? CREATE OBJECT o_circle.
?? CALL METHOD o_circle->get_area
?????????????? EXPORTING i_radius = radius
?????????????? RECEIVING r_size = area.
?? WRITE: / area.
?? area = o_circle->get_area( radius ).
?? WRITE: / area.

構(gòu)造方法和析構(gòu)方法
1. 構(gòu)造方法
??? 構(gòu)造方法是運(yùn)行時(shí)環(huán)境自動(dòng)調(diào)用的一種方法,用于為對(duì)象設(shè)定一個(gè)初始化狀態(tài),不能在程序運(yùn)行過程中由程序代碼調(diào)用.與其他方法類似構(gòu)造方法也存在靜態(tài)和實(shí)例兩種形式.構(gòu)造方法不一定需要在類中定

義,系統(tǒng)通常會(huì)自動(dòng)生成一個(gè)默認(rèn)的構(gòu)造方法,將對(duì)象狀態(tài)設(shè)置為初始值.
構(gòu)造方法中不包含任何形式的輸出參數(shù),其功能只是定義對(duì)象狀態(tài),而不是對(duì)其進(jìn)行改變.構(gòu)造方法在create object語句中被調(diào)用,因此根據(jù)實(shí)例構(gòu)造方法的定義,該語句本身也可以包含輸出參數(shù)exporting和

返回值exception選項(xiàng).如果在對(duì)象創(chuàng)建過程中出現(xiàn)異常,則對(duì)象被刪除,引用變量設(shè)為初始值.
???? 類構(gòu)造方法屬于靜態(tài)方法,只能在程序中被調(diào)用一次,即第一次使用該類時(shí)調(diào)用,該方法也必須在公有部分聲明,其名稱必須為class_constructor.
???? class-methods class_constructor.
???? 類構(gòu)造方法不包含接口,而且在其中只能訪問類的靜態(tài)屬性.
構(gòu)造方法:?
REPORT z_method_constructor.
*---------------------------------------------------------------------*
*??????? CLASS vehicle DEFINITION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
CLASS vehicle DEFINITION.
?? PUBLIC SECTION.
???? METHODS: accelerate IMPORTING rate TYPE i,
????????????? constructor IMPORTING i_speed TYPE i,
????????????? show_speed.
?? PRIVATE SECTION.
???? DATA speed TYPE i VALUE 0.
ENDCLASS.
*---------------------------------------------------------------------*
*??????? CLASS vehicle IMPLEMENTATION
*---------------------------------------------------------------------*
*??????? ........?????????????????????????????????????????????????????? *
*---------------------------------------------------------------------*
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.
?? CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
?? CALL METHOD o_vehicle->accelerate EXPORTING rate = 2.
?? CALL METHOD o_vehicle->show_speed.
該示例輸出如下:?
????? 8
在對(duì)象創(chuàng)建過程中,通過構(gòu)造方法傳遞了一個(gè)速度初始值作為其初始狀態(tài).
2. 析構(gòu)方法
??? 在某些面向?qū)ο笳Z言中還存在析構(gòu)方法的概念,該方法在對(duì)象刪除過程中被調(diào)用,目前ABAP對(duì)象中尚未提供該方法的實(shí)現(xiàn)形式.

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