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HP OpenVMS Systems Documentation |
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HP COBOL
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In Figures 11-14 and 11-15, the output from the sample program is shown.
Figure 11-14 MENU-SCREEN Output (Alpha, I64)
+------------------------------------------------------------------------------+ | Daily Calendar | | | | | | || | | | | Show appointments for a day | | | | Schedule an appointment | | | | Cancel an appointment | | | | Print your appointments | | | | | | | | | | | | Use the arrow keys to move the cursor among menu items. | | Press <Return> when the cursor is at the desired item. | | Press <F10> to exit. | | | | || | | | +------------------------------------------------------------------------------+ |
Figure 11-15 SCHEDULE-SCREEN Output (Alpha, I64)
+------------------------------------------------------------------------------+ | Schedule Appointment | | | | | | | | Description of Appointment: | |Meeting with Bill and Susan | | | | | | Date of Appointment (DD/MM/YY): 01/03/94 | | | | Time of Appointment (HH:MM mm): 11:00 AM | | | | | | | | | | Use Cursor Keys to move within the fields. | | Press <Tab> to enter next field. | | Press <Return> when finished. | | | | | | | | | +------------------------------------------------------------------------------+ |
COBOL programs can communicate with each other, as well as with non-COBOL programs. Program-to-program communication is conducted by using one (or combinations) of the following:
This chapter includes the following information about interprogram communication:
A multiple COBOL program run unit consists of either of the following:
Separately compiled programs can be concatenated in one source file, or
can be written as separate source files.
12.1.1 Examples of COBOL Run Units
Example 12-1 shows a run unit with three separately compiled programs, none of which have contained programs. MAIN-PROGRAM ((1)) calls separate program SUB1 ((2)), that calls separate program SUB2 ((3)).
| Example 12-1 Run Unit with Three Separately Compiled Programs |
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IDENTIFICATION DIVISION. IDENTIFICATION DIVISION.
PROGRAM-ID. MAIN-PROGRAM. (1) PROGRAM-ID. SUB1. (2)
. .
. .
. .
CALL SUB1. CALL SUB2.
. .
. .
. .
STOP RUN. EXIT PROGRAM.
END PROGRAM MAIN-PROGRAM END PROGRAM SUB1.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB2. (3)
.
.
.
EXIT PROGRAM.
END PROGRAM SUB2.
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A separately compiled program has a nesting level number of 1. If this program contains other source programs, it is the outermost containing program. A contained program has a nesting level number greater than 1. |
Example 12-2 shows a run unit with one main program ((4)) and two contained programs (SUB1 ((5)) is a directly contained program of MAIN-PROGRAM; SUB2 ((6)) is an indirectly contained program of MAIN-PROGRAM).
| Example 12-2 Run Unit with a Main Program and Two Contained Programs |
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IDENTIFICATION DIVISION.
PROGRAM-ID. MAIN-PROGRAM. (4)
.
.
.
CALL SUB1.
.
.
.
STOP RUN.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB1. (5)
.
.
.
CALL SUB2.
EXIT PROGRAM.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB2. (6)
.
.
.
EXIT PROGRAM.
END PROGRAM SUB2.
END PROGRAM SUB1.
END PROGRAM MAIN-PROGRAM.
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Example 12-3 shows a run unit with three separately compiled programs ((7), (10), and (11)). One of the separately compiled programs, MAIN-PROGRAM ((7)), has two directly contained programs, SUB1 and SUB2 ((8) and (9)).
| Example 12-3 Run Unit with Three Separately Compiled Programs, One with Two Contained Programs |
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IDENTIFICATION DIVISION.
PROGRAM-ID. MAIN-PROGRAM. (7)
.
.
.
CALL SUB1.
CALL SUB2.
.
STOP RUN.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB1. (8)
.
.
.
CALL SUB3.
EXIT PROGRAM.
END PROGRAM SUB1.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB2. (9)
.
.
.
EXIT PROGRAM.
END PROGRAM SUB2.
END PROGRAM MAIN-PROGRAM.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB3. (10)
.
.
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CALL SUB4.
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.
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STOP RUN.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUB4. (11)
.
.
.
EXIT PROGRAM.
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