ABAP Basic Concept 2 n n IF CASE
ABAP Basic Concept (2) n n 運算子 控制式與迴圈 – IF, CASE, DO… ENDDO n Subroutines – Call by value, value and result, reference n Event Block – Initialization, Start-of-Selection, At Line-Selection ABAP 楊子青 1
2. 控制式與迴圈 n IF子句 IF <Logical Expression>. <Statements>. ELSE. <Statements>. ENDIF. n CASE子句 CASE < variable >. WHEN 'value 1'. <Statements>. WHEN 'value 2' OR 'value 3'. <Statements>. WHEN OTHERS. <Statements>. ENDCASE. ABAP 楊子青 3
控制式與迴圈 (Cont. ) n DO…ENDDO子句 DO 整數變數 TIMES. ENDDO. – 範例： DATA X TYPE I. DATA N TYPE I. X = 1. N = 5. DO N TIMES. WRITE: / X. X = X + 1. ENDDO. ABAP 楊子青 4
3. Subroutines n 第一行以FORM開始，最後一行以 ENDFORM結束 ABAP 楊子青 5
練習F參考解答 REPORT zyy. TC_EX_F. DATA N TYPE I. N = 6. PERFORM SQUARE 1 USING N. WRITE: / 'N=', N. ULINE. PERFORM SQUARE 2 CHANGING N. WRITE: / 'N=', N. FORM SQUARE 1 USING VALUE(X). X = X * X. WRITE: / 'Square 1: N^2=', X. ENDFORM SQUARE 2 CHANGING X. X = X * X. WRITE: / 'Square 1: N^2=', X. ENDFORM. ABAP 楊子青 8
Event Blocks for Reports ABAP 楊子青 10
Event Blocks for Reports (Cont. ) n n n The runtime environment creates the INITIALIZATION event and calls the event block. If there is a selection screen defined in the program, control returns to the selection screen processor. Control then passes to the reporting processor. It creates the START-OF-SELECTION event. The logical database, if you are using one, calls further event blocks at this point. The reporting processor creates the END-OFSELECTION event. If the program contains a list description, it displays the list defined in the AT LINE-SELECTION event. ABAP 楊子青 11
Major Event Blocks 設定初值 Basic list要用到的 event，用來產生report 範例 PARAMETERS INPUTN TYPE I. START-OF-SELECTION. IF INPUTN = 1. WRITE : 'HI!'. ENDIF. ABAP 楊子青 12
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