*> ============================================================
      *> callee : 计费子程序被调用侧 (Billing Subprogram Callee)
      *> Input : LS-NUM1, LS-NUM2 (LINKAGE参数)
      *> Output: LS-RESULT (计算结果返却)
      *> Coverage: C-N001~N008, C-A001, C-R001, C-R002
      *> ============================================================
       IDENTIFICATION DIVISION.
       PROGRAM-ID. callee.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-INITIALIZED     PIC X VALUE 'N'.
           88 WS-INITIALIZED-YES VALUE 'Y'.

       LINKAGE SECTION.
       01 LS-NUM1            PIC 9(10).
       01 LS-NUM2            PIC 9(10).
       01 LS-RESULT          PIC 9(10).

       PROCEDURE DIVISION USING LS-NUM1 LS-NUM2 LS-RESULT.
           IF NOT WS-INITIALIZED-YES
               DISPLAY "callee: FIRST CALL"
               SET WS-INITIALIZED-YES TO TRUE
           END-IF

           COMPUTE LS-RESULT = LS-NUM1 + LS-NUM2
           MOVE 0 TO RETURN-CODE
           GOBACK
           .

       END PROGRAM callee.