3.1.1 MOVE Statement
The MOVE statement copies data from one area of storage to one (more) other areas.
MOVE identifier-1 TO identifier-2 ????.
MOVE literal TO identifier-2 ????.
Identifiers may be either elementary or group items.
A POINTER data-item, or an index data-item, cannot be specified in a MOVE.
3.1.2 Elementary Moves
- Both sending and receiving data-items are elementary items.
- Data conversion may take place, as well as editing or de-editing.
- On alphabetic moves, may necessary space-fill or truncation will
3.1.3 Group Moves
- Both sending and receiving data-items are group items.
- No data conversion takes place.
MOVE EXAMPLE
WORKING-STORAGE SECTION.
01 GROUP-VARIABLES.
04 VAR-1 PIC X(1).
04 VAR-2 PIC X(2).
04 VAR-3 PIC X(3).
04 VAR-4 PIC X(4).
PROCEDURE DIVISION.
MOVE SPACES TO GROUP-VARIABLES-1.
| b | b | b | b | b | b | b | b | b | b |
MOVE ?XY? TO VAR-1 VAR-3.
| X | b | b | X | Y | b | b | b | b | b |
MOVE ALL ?*? TO VAR-4.
| X | b | b | X | Y | b | * | * | * | * |
MOVE ALL ?AB? TO VAR-3.
| X | b | b | A | B | A | * | * | * | * |
3.2 Arithmetic verbs
Intermediate results of arithmetic statements are possible when:
- ADD or SUBTRACT with multiple operands following the verb.
- COMPUTE with multiple result fields.
- Arithmetic expressions in reference modifications
- Use of multiple results in the GIVING phrase of ADD, SUBTRACT,
The maximum size of each arithmetic operand is 18 decimal digits, but a hypothetical ?composite of operands? can be up to 30 decimal digits.
The following example has a composite of operands with implicit description of PIC 9(12)V9(5) or 17 decimal digits.
DATA DIVISION.
77 FLD1 PIC 9(7)V9(5).
77 FLD2 PIC 9(11)V99.
77 FLD3 PIC 9(12)V9(3).
PROCEDURE DIVISION.
ADD FLD1, FLE2 GIVING FLD3
ADD Statement
ADD identifier-1A identifier-1B ????.
To identified ? 2A [ROUNDED]
identifier-2B ????.
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[END-ADD]
- The identifiers (or literals) preceding the word TO are added together, and then this sum is added to, and replaces, each identifier-2. The action is repeated, In left-to-right order, for each identifier-2.
- Identifiers must be elementary numeric items.
- ADD is not allowed with items having USAGE POINTER.
ADD amount-1 amount-2 TO amount-3
ADD amount-1 TO amount-2 amount-3.
ADD 1 TO employee-count.
SUBTRACT Statement
SUBTRACT identifier-1A identifier-1B ???FROM identifier-2A [ROUNDED]
identifier-2B identifier-2C ????.
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[END-SUBTRACT]
- All identifiers (or literals) preceding the word FROM are added together, and then this sum is subtracted from, and replaces, identifier-2. The action is repeated, in left-to-right order, for each identifier-2.
- Identifiers must be elementary numeric items.
- SUBTRACT is not allowed with items having USAGE POINTER.
MULTIPLY Statement
MULTIPLY identifier-1 BY identifier-2A [ROUNDED] identifier-2B identifier-2C ????.
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[END- MULTIPLY]
- The identifier (or literal) is multiplied by identifier-2; the product replaces.identifier-2. The action is repeated, in left-to-right order, for each identifier-2.
- Identifiers must be elementary numeric items.
77 SALES-TAX PIC 99999V99.
77 MERCHANDISE PIC 99999V99.
PROCEDURE DIVISION.
MULTIPLY MERCHANDISE BY .0675 GIVING SALES-TAX ROUNDED.
DIVIDE Statement
DIVIDE identifier-1
INTO identifier-2A [ROUNDED]
identifier-2B identifier-2C ??..
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[REMAINDER identifier-3]
[END- DIVIDE]
- The value of the first identifier (or literal) is divided into the value of
repeated, in left-to-right order, for each identifier-2.
- Identifiers must be elementary numeric items.
- The SIZE ERROR execution occurs if division by zero is attempted.
DIVIDE identifier-1 INTO identifier-2 GIVING identifier-3A [ROUNDED]
Identifier-3B identifier-3C ??..
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[END- DIVIDE]
DIVIDE identifier-1
BY identifier-2
GIVING identifier-3A [ROUNDED]
Identifier-3B identifier-3C ??..
[END- DIVIDE]
- The value of the first identifier (or literal) is divided into (or by) the value of identifier-2; the quotient replaces identifier-3. The action is repeated, in left-to-right order, for each identifier-3.
- Identifiers-1 and -2 must be elementary numeric items.
- Identifier-3 may be a numeric-edited item.
COMPUTE identifier-1A [ROUNDED]
identifier-1B identifier-1C ??..
EQUAL(=) arithmetic-expression
[ON SIZE ERROR??..]
[NOT ON SIZE ERROR??..]
[END- COMPUTE]
- Identifier-1 may name elementary numeric items or numeric-edited items.
- The arithmetic expression is calculated and replaces the value for each identifier-1item.
- Arithmetic operators allowed in the expression are:
- (subtraction)
* (multiplication)
/ (division)
** (exponentiation)
Example
COMPUTE
FINAL-VAL ROUNDED = BASIC-VAL * 1.5
END-COMPUTE.
3.3 Table handling
Table-handling is fundamental to data processing. A table is a collection of logically related entries. A table is a set of values stored in consecutive storage locations and assigned one variable. Any reference to specific entries in the table, is made by the use of the variable along with a subscript that identifies the location of a particular entry. While an array stores data to be output, a table is used for looking up or referencing data.
So, instead of defining n data-names in the WORKING-STORAGE SECTION the same can be defined like this :
E.g. 01 WEEK-TABLE.
05 DAY OCCURS 7 TIMES PIC X(9).
Use of the OCCURS clause along with the PICTURE clause, helps the programmer to create tables so that reference can be made to entire tables or individual values by means of a subscript. In the example, 7 memory locations are set aside, each of which will hold a 9 character alphabetic string.
A DATA DIVISION entry involving an OCCURS clause, includes the name assigned to the table, the number of rows and columns (the dimension), the number of entries in each dimension, and the field characteristics of each entry. An individual entry is indicated by assigning a subscript within brackets after the data-name. These individual entries are called elements.
Now the first DAY in the WEEK-TABLE can be referred as DAY(1). Similarly the 7th entry in the table can be referred to as DAY(7). Thus each element is assigned a numeric value which is called the subscript. Now, a specific element in the table is accessed by the use of subscripts. The subscript can be represented either by a literal or by a data-name which is defined elsewhere as a numeric elementary data-item.
E.g. DAY(1) or DAY(CTR)
where CTR is a data-item defined as a numeric data-name. So, if the value
of CTR is 1, then you are actually referring to the first occurrence in the
WEEK-TABLE.
WEEK-TABLE
| S | U | N | D | A | Y | |||
| M | O | N | D | A | Y | |||
| T | U | E | S | D | A | Y | ||
| W | E | D | N | E | S | D | A | Y |
| T | H | U | R | S | D | A | Y | |
| F | R | I | D | A | Y | |||
| S | A | T | U | R | D | A | Y |
E.g.
*The program creates a table of student marks, calculates the total and average.
IDENTIFICATION DIVISION.
PROGRAM-ID. MARK-CAL.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 TOT PIC 9(4) VALUE 0.
01 AVG PIC 9(3) VALUE 0.
01 CTR PIC 9(2) VALUE 0.
01 MARKS-TABLE.
03 MARKS OCCURS 7 TIMES PIC 9(3).
PROCEDURE DIVISION.
MAIN-PARA.
PERFORM ENTER-PARA VARYING CTR FROM 1 BY 1 UNTIL CTR > 7.
MOVE 0 TO TOT.
PERFORM TOTAL-PARA VARYING CTR FROM 1 BY 1 UNTIL CTR > 7.
PERFORM DISPLAY-PARA.
GOBACK.
ENTER-PARA.
DISPLAY "ENTER MARKS FOR SUBJECT : ", CTR.
ACCEPT MARKS(CTR).
TOTAL-PARA.
ADD MARKS(CTR) TO TOT.
DISPLAY-PARA.
COMPUTE AVG ROUNDED = TOT / 7.
DISPLAY "THE TOTAL MARK IS : ", TOT.
DISPLAY "THE AVERAGE IS : ", AVG.
IF AVG >= 60
DISPLAY "FIRST CLASS"ELSE IF AVG >= 50
DISPLAY "SECOND CLASS"
ELSE IF AVG >= 40
DISPLAY "THIRD CLASS"
ELSE
DISPLAY "FAIL".
STOP " ".
Here, MARKS-TABLE is a group data-item and is therefore defined as a 01 level entry. Each data-item is called MARKS which has 7 items.
OCCURS clause
The OCCURS clause, on a data definition, specifies tables whose elements can be referred to by indexing or subscripting.
OCCURS integer [ TIMES ] [ ASCENDING [ KEY IS ] data-name-2 ] [ INDEXED BY index-name-1 ] |
OCCURS integer [ TIMES ] [ DESCENDING [ KEY IS ] data-name-2 ] [ INDEXED BY index-name-1 ] |
- Fixed-length tables allow 7 level of nesting.
- ?integer? is the exact number of occurrences (must be > 0).
- The ASCENDING / DESCENDING KEY phrase is needed for a ?binary search? of the table with SEARCH ALL statement.
- A key-field may have USAGE DISPLAY, BINARY, PACKED-DECIMAL, amongst others.
SUBSCRIPTING
Subscripting is a means of providing table references. A subscript is a positive number whose value indicates the occurrence of a table element.
Seven levels of subscripting are allowed.
Subscripts are enclosed in parentheses.
The number of subscripts must equal the number of dimensions in the table being referenced.
Example
01 TABLE-THREE.
05 ELEMENT-1 OCCURS nn TIMES.
10 ELEMENT-2 OCCURS nn TIMES.
15 ELEMENT-3 OCCURS nn TIMES PIC X(8).
MOVE ELEMENT-3 (1, 2, 1) TO ???..
MOVE ELEMENT-3 (SUB1 SUB1 SUB1) TO ??.
Indexing
An ?index-name? is an identifier that becomes associated with a particular table. The value in an index is the displacement from the beginning of the table based upon the length of the table element.
An ?index-name? may appear on an OCCURS clause, e.g.
01 TABLE-OF-MONTHS.
02 MONTHS OCCURS 12 TIMES PIC X(10) INDEXED BY NDX.
The ?index-name? is created by the compiler; it does not have to be defined elsewhere in the program.
The actual value in an index is determined by the following formula;
I = L * ( S ? 1 )
Where I is the index value; L is the length of a table element; S is the occurrence number of the entry.
The contents of an index may be changed by the SET TO statement. An index may not be used in a MOVE statement or an INITIALIZE statement.
Subscript Vs Index
| Subscript | Index |
| Represents an occurance of a Table element | Represents the displacement from the address of the first element in table. |
| Is defined explicitly in working-storage section | An index is a special subscript created and Maintained by the OS. |
| To change value of subcript, use a PERFORM .. VARYING or a MOVE , ARITHMETIC statement | To change the value of Index use PERFORM .. VARYING or a SET statement. |
SEARCH statement ? serial
SEARCH identifier
[ VARYING index-name ]
[ AT END imperative ?.] -? when no occurrence found
WHEN condition-1 imperative ?.
[ WHEN condition-1 NEXT SENTENCE ]
[END-SEARCH ]
SEARCH statement ? binary
SEARCH ALL identifier
[ AT END imperative ]
WHEN condition-1
[AND condition-2]?.
Imperative [END-SEARCH]
Condition : The identifier must contain an OCCURS clause with KEY IS phrase.
SET INDEX STATEMENT
Different SET statements.
SET index-name TO integer
SET index-name to identifier
SET index-name to index-name-1
SET index-name-1 UP/DOWN BY integer / identifier
SERIAL SEARCH.
WORKING-STORAGE SECTION.
01 WHOLE-TABLE.
02 TABLE-ELMT OCCURS nn TIMES
INDEXED BY NDX.
10 KEYFIELD ?
PROCEDURE DIVISION.
SEARCH TABLE-ELMT VARYING NDX
WHEN KEYFIELD(NDX) = SEARCH-ARG
SET FOUND TO TRUE
WHEN KEYFIELD(NDX) = HIGH-VALUES
SET NOT-FOUND TO TRUE
END-SEARCH
IF FOUND
???.
ELSE
DISPLAY SEARCH-ARG ?NOT IN TABLE ?
END-IF
BINARY SEARCH
LINKAGE SECTION.
01 WHOLE-TABLE.
03 TABLE-ELMT OCCURS 1 TO 250 TIMES
DEPENDING ON PARM2
ASCENDING KEY IS KEYFIELD INDEXED BY NDX.
05 KEYFIELD PIC X(n).
05 ??
PROCEDURE DIVISION.
MOVE ?. TO PARM2
SET ADDRESS OF WHOLE-TABLE TO TABLE-POINTER
SEARCH ALL TABLE-ELMT
WHEN KEYFIELD(NDX) = SEARCH-ARG
SET FOUND TO TRUE
END-SEARCH
IF FOUND
END-IF.
PERFORM Statement
PERFORM is a sequence control statement that causes the program to branch out to another procedure or a series of procedures and following the execution, it returns to the point it branched out from. The procedure is treated as a sub-routine, and the PERFORM statement in the main routine provides a link to and from the sub-routines.
1. SIMPLE PERFORM
PERFORM PARA-1.
DISPLAY ?PARA-1 executed?
STOP RUN.
PARA-1.
Statement1
Statement2.
It executes all the instructions coded in PARA-1 and then transfers the control to the next instruction in sequence.
2. INLINE PERFORM.
When sets of statements are used only in one place then we can group all of them within PERFORM END-PERFORM structure. This is called INLINE PERFORM. This is equal to DO..END structure of other languages.
PERFORM
ADD A TO B
MULTIPLY B BY C
DISPLAY ?VALUE OF A+B*C? C
END-PERFORM
3. PERFORM PARA-1 THRU PARA-N.
All the paragraphs between PARA-1 and PARA-N are executed once.
4. PERFORM PARA-1 THRU PARA-N UNTIL conditions(s).
The identifiers used in the UNTIL condition(s) must be altered within the paragraph(s) being performed; otherwise the paragraphs will be performed indefinitely. If the condition in the UNTIL clause is met at first time of execution, then named paragraph(s) will not be executed at all.
5. PERFORM PARA-1 THRU PARA-N N TIMES.
N can be literal defined as numeric item in working storage or hard coded constant.
6. PERFORM PARA-1 THRU PARA-N VARYING identifier1
FROM identifier 2 BY identifier3 UNTIL condition(s)
Initialize identifier1 with identifier2 and test the conditions(s). If the condition is false execute the statements in PARA-1 thru PARA-N and increment identifiere1 BY identifier3 and check the condition(s) again. If the condition is again false, repeat this process till the condition is satisfied.
7. PERFORM
With TEST BEFORE condition is checked first if it is found to be false then PARA-1 will be executed and this is the default.
With TEST AFTER PARA-1 is executed once and then the condition is checked.
3.4 Input ? Output statement
OPEN Statement
OPEN INPUT filename ???
OPEN OUTPUT filename ???
OPEN I-O filename???
OPEN EXTEND filename ???
The phrase INPUT, OUTPUT, I-O, or EXTEND must appear at least once (but may be in any order).
Example
DATA DIVISION.
FILE SECTION.
FD INVOICE
RECORD CONTAINS 80
RECORDING MODE F.
FD PRINTOUT
RECORD CONTAINS 132.
PROCEDURE DIVISION.
OPEN INPUT INVOICE
OPEN OUTPUT PRINTOUT
CLOSE Statement
CLOSE filename1 , filename2??. |
CLOSE filename1 filename2 |
The CLOSE statement terminates the processing of files; a close may be executed only for file in open mode.
After CLOSE processing, the record area associated with the file is no longer available.
The CLOSE WITH LOCK phrase ensures that the file cannot be opened again during the execution.
The CLOSE WITH NO REWIND phrase exists to ensure that the volume is left in its current position.
Example
DATA DIVISION.
FILE SECTION.
FD INVOICE
RECORD CONTAINS 80
RECORDING MODE F.
FD PRINTOUT
RECORD CONTAINS 132.
RECORDING MODE F.
PROCEDURE DIVISION.
??????
??????..
CLOSE INVOICE PRINTOUT
READ ? SEQUENTIAL ACCESS
READ filename
[NEXT] [RECORD]
[AT END??..]
[NOT AT END???]
[END-READ]
For sequential access, the READ statement makes the next logical record available to the program. The NEXT RECORD accessed is determined by the file organization.
When the READ statement is executed, the file already be open in INPUT or I-O mode
If SELECT OPTIONAL was specified in FILE-CONTROL, and the file is absent, execution of the first READ cause an AT END condition.
The ?AT END ?.? Clause must appear before the ?NOT AT END?? clause.
SEQUENTIAL PROCESSING SAMPLE
( Pseudocode )
PERFORM UNTIL end-of file
READ next-record
AT END SET end-of-file TO TRUE
NOT AT END process-the-record
END-PERFORM.
READ ? RANDOM ACCESS
READ filename
[ RECORD ]
[ INTO identifier ]
[ KEY IS dataname ]
[ INVALID KEY . . . ]
[ NOT INVALID K. . .]
[ END-READ ]
FORMAT 2
Format 2 must be specified for random record retrieval.
- For a VASAM INDEXED file ,the KEY field contains a data value that will be matched against the key field in the records until the first record having an equal value is found.
- For a VSAM RELATIVE file ,the KEY phrase must not be specified.
- When the READ statement is executed, the file must already open in INPUT or I-O mode.
READ ? DYNAMIC ACCESS
READ filename NEXT [RECORD] [INTO identifier] [AT END??..] [NOT AT END???] [END-READ] |
READ filename [RECORD] [INTO identifier] [key is DATANAME] [INVALID KEY?..] [NOT INVALID KEY?..] [END-READ] |
For dynamic access, either sequential or random access is possible, depending upon the format of the READ statement.
- Dynamic access is allowed only for VSAM indexed or VSAM relative organization. (Established by ACCESS IS DYNAMIC in FILE-CONTROL SECTION statement).
- The NEXT phrase must be specified for sequential access with dynamic mode. In order to READ NEXT, ?position? must have been established in the file by a successful OPEN, START, or READ statement.
| WRITE record-name [ FROM identifier ] [ AFTER ADVANCING nnn LINES ] [ AT END-OF ?PAGE . . . ] [ NOT AT END ?OF- PAGE . . . ] [ END- WRITE ] |
| WRITE record ? name [ FROM identifier ] [ BEFORE ADVANCING nnn LINE [ S ] ] [ AT END-OF-PAGE . . . ] [ NOT AT END-OF-PAGE ] [ END- WRITE ] |
FORMAT (QSAM)
RECORD-NAME mist be defined via Data Division FD entry.
FROM option yields results identical to:
MOVE identifier TO record-name
WRITE record ?name
- When the ADVANCING clause is omitted automatic line advancing is provided
WRITE . . . . .AFTER ADVANCING 1 LINE.
- A further positioning operand is AFTER / BEFORE ADVANCING PAGE.
ACCEPT identifier
[FROM mnemonic-name]
The ?mnemonic-name? must be associated with a device in the SPECIAL-NAMES paragraph.
When FROM phrase is omitted, SYSIN is the default.
The identifier may be a group or elementary item.
EXAMPLE
77 SEARCH-VALUE PIC X(10).
??????..
PROCEDURE DIVISION.
ACCEPT SEARCH-VALUE FROM SYSIN.
???
ACCEPT Statement
ACCEPT identifier FROM DATE
ACCEPT identifier FROM DAY
ACCEPT identifier FROM DAY-OF-WEEK
ACCEPT identifier FROM TIME
DATE has implicit PICTURE 9(6) (YYMMDD).
DAY has implicit PICTURE 9(5) (YYDDD).
DAY-OF-WEEK has implicit PICTURE 9(1) where the value ?1? represents Monday, ?2? implies Tuesday, etc.
- TIME has implicit PICTURE 9(8) (HHMMSSTH).
01 TODAY.
02 THIS-YEAR PIC 99.
02 THIS-MONTH PIC 99.
02 THIS-DAY PIC 99.
01 CURRENT-DATE.
02 THIS-MONTH PIC Z9.
02 FILLER PIC X VALUE ?/?.
02 THIS-DAY PIC 99.
02 FILLER PIC X VALUE ?/?.
02 THIS-YEAR PIC 99.
PROCEDURE DIVISION.
ACCEPT TODAY FROM DATE
MOVE CORR TODAY TO CURRENT-DATE
___________________________________________________________
DISPLAY STATEMENT
DISPLAY identifier ?1 identifier ?2. . . .
[ UPON mnemonic-name ]
If the identifier is numeric (but not external decimal), the contents are converted to an external format.
When the UPON phrase in omitted, the default device in SYSOUT.
Example
ENVIROMENT DIVISION.
CONFIGURATION SECTION.
SPECIAL-NAMES . SYSOUT IS SYSPRINT.. . . . .
PROCEDURE
DISPLAY SRCH-ARG ? NOT IN TABLE. ?
DISPLAY SRCH-ARG SPACES ? NOT IN TABLE. ?
3.5 Conditional Verbs & sequence control verbs
3.5.1 IF Statement
IF EMPNO < PREV-EMPNO
MOVE ?OUT OF ORDER? TO MESSAGE-TXT
PERFORM ERROR-MESSAGE
ADD 1 TO INVALID-COUNTER
ELSE
MOVE EMPNO TO PREV-EMPNO
END-IF.
05 EMPL-STATUS PIC X.
88 SECRATARY VALUE ?S?.
88 APPRENTICE VALUE ?A?.
88 WORKER VALUE ?W?.
88 MANAGER VALUE ?M?.
88 NONE-OF-ABOVE VALUE ?N?.
IF SECRETARY
PERFORM ADMIN-PROCESS
_________________________________________________________________
05 EMPL-STATUS PIC X.
88 SECRATARY VALUE ?S?.
88 APPRENTICE VALUE ?A?.
88 WORKER VALUE ?W?.
88 MANAGER VALUE ?M?.
88 NONE-OF-ABOVE VALUE ?N?.
IF EMPL-STATUS = ?S?
PERFORM ADMIN-PROCESS
The two techniques for testing are equivalent.
3.5.2 CONTINUE Statement
The CONTINUE statement allows you to specify ?no operation ? where an imperative statement is expected.
Example1 ? ?NEXT SENTENCE ?
IF A = B
IF C = D
NEXT SENTENCE
ELSE
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
ADD C TO TOTAL
IF E = F
MOVE MESSAGE-4 TO RPT-MESSAGE-2
END-IF
END-IF
Control comes here
Next instruction
Example 2 ? ?CONTINUE ?
IF A = B
IF C = D
CONTINUE
ELSE
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
Control comes here
ADD C TO TOTAL
IF E = F
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
END-IF
Next instruction
3.5.3 EVALUATE Statement
The COBOL II EVALUATE statement provides a technique for coding similarly to the structured design CASE construct.
EVALUATE is an alternative to nested IF?s.
?WHEN? phrase can be written similar to a logic table.
The organization of the EVALUATE STATEMENT IS:
EVALUATE
Identifier
Literal
Expression
True
FALSE
WHEN
Condition
TRUE
FALSE
ANY
Literal
Identifier
Arithmetic expression
Operand(s) before the WHEN phrase is/are called selection subject(s)
Operand(s) within the WHEN phrase is/are called selection subject(s)
The must be the same number of selection subjects as selection objects.
PERFORM Statement
PERFORM is a sequence control statement that causes the program to branch out to another procedure or a series of procedures and following the execution, it returns to the point it branched out from. The procedure is treated as a sub-routine, and the PERFORM statement in the main routine provides a link to and from the sub-routines.
1. SIMPLE PERFORM
PERFORM PARA-1.
DISPLAY ?PARA-1 executed?
STOP RUN.
PARA-1.
Statement1
Statement2.
It executes all the instructions coded in PARA-1 and then transfers the control to the next instruction in sequence.
When sets of statements are used only in one place then we can group all of them within PERFORM END-PERFORM structure. This is called INLINE PERFORM. This is equal to DO..END structure of other languages.
PERFORM
ADD A TO B
MULTIPLY B BY C
DISPLAY ?VALUE OF A+B*C? C
END-PERFORM
3. PERFORM PARA-1 THRU PARA-N.
All the paragraphs between PARA-1 and PARA-N are executed once.
4. PERFORM PARA-1 THRU PARA-N UNTIL conditions(s).
The identifiers used in the UNTIL condition(s) must be altered within the paragraph(s) being performed; otherwise the paragraphs will be performed indefinitely. If the condition in the UNTIL clause is met at first time of execution, then named paragraph(s) will not be executed at all.
5. PERFORM PARA-1 THRU PARA-N N TIMES.
N can be literal defined as numeric item in working storage or hard coded constant.
6. PERFORM PARA-1 THRU PARA-N VARYING identifier1
FROM identifier 2 BY identifier3 UNTIL condition(s)
Initialize identifier1 with identifier2 and test the conditions(s). If the condition is false execute the statements in PARA-1 thru PARA-N and increment identifiere1 BY identifier3 and check the condition(s) again. If the condition is again false, repeat this process till the condition is satisfied.
7. PERFORM
With TEST BEFORE condition is checked first if it is found to be false then PARA-1 will be executed and this is the default.
With TEST AFTER PARA-1 is executed once and then the condition is checked.
3.4 Input ? Output statement
OPEN Statement
OPEN INPUT filename ???
OPEN OUTPUT filename ???
OPEN I-O filename???
OPEN EXTEND filename ???
The phrase INPUT, OUTPUT, I-O, or EXTEND must appear at least once (but may be in any order).
Example
DATA DIVISION.
FILE SECTION.
FD INVOICE
RECORD CONTAINS 80
RECORDING MODE F.
FD PRINTOUT
RECORD CONTAINS 132.
PROCEDURE DIVISION.
OPEN INPUT INVOICE
OPEN OUTPUT PRINTOUT
CLOSE Statement
CLOSE filename1 , filename2??. |
CLOSE filename1 filename2 |
The CLOSE statement terminates the processing of files; a close may be executed only for file in open mode.
After CLOSE processing, the record area associated with the file is no longer available.
The CLOSE WITH LOCK phrase ensures that the file cannot be opened again during the execution.
The CLOSE WITH NO REWIND phrase exists to ensure that the volume is left in its current position.
Example
DATA DIVISION.
FILE SECTION.
FD INVOICE
RECORD CONTAINS 80
RECORDING MODE F.
FD PRINTOUT
RECORD CONTAINS 132.
RECORDING MODE F.
PROCEDURE DIVISION.
??????
??????..
CLOSE INVOICE PRINTOUT
READ ? SEQUENTIAL ACCESS
READ filename
[NEXT] [RECORD]
[AT END??..]
[NOT AT END???]
[END-READ]
For sequential access, the READ statement makes the next logical record available to the program. The NEXT RECORD accessed is determined by the file organization.
When the READ statement is executed, the file already be open in INPUT or I-O mode
If SELECT OPTIONAL was specified in FILE-CONTROL, and the file is absent, execution of the first READ cause an AT END condition.
The ?AT END ?.? Clause must appear before the ?NOT AT END?? clause.
SEQUENTIAL PROCESSING SAMPLE
( Pseudocode )
PERFORM UNTIL end-of file
READ next-record
AT END SET end-of-file TO TRUE
NOT AT END process-the-record
END-PERFORM.
READ ? RANDOM ACCESS
READ filename
[ RECORD ]
[ INTO identifier ]
[ KEY IS dataname ]
[ INVALID KEY . . . ]
[ NOT INVALID K. . .]
[ END-READ ]
Format 2 must be specified for random record retrieval.
- For a VASAM INDEXED file ,the KEY field contains a data value that will be matched against the key field in the records until the first record having an equal value is found.
- For a VSAM RELATIVE file ,the KEY phrase must not be specified.
- When the READ statement is executed, the file must already open in INPUT or I-O mode.
READ filename NEXT [RECORD] [INTO identifier] [AT END??..] [NOT AT END???] [END-READ] |
READ filename [RECORD] [INTO identifier] [key is DATANAME] [INVALID KEY?..] [NOT INVALID KEY?..] [END-READ] |
For dynamic access, either sequential or random access is possible, depending upon the format of the READ statement.
- Dynamic access is allowed only for VSAM indexed or VSAM relative organization. (Established by ACCESS IS DYNAMIC in FILE-CONTROL SECTION statement).
- The NEXT phrase must be specified for sequential access with dynamic mode. In order to READ NEXT, ?position? must have been established in the file by a successful OPEN, START, or READ statement.
| WRITE record-name [ FROM identifier ] [ AFTER ADVANCING nnn LINES ] [ AT END-OF ?PAGE . . . ] [ NOT AT END ?OF- PAGE . . . ] [ END- WRITE ] |
| WRITE record ? name [ FROM identifier ] [ BEFORE ADVANCING nnn LINE [ S ] ] [ AT END-OF-PAGE . . . ] [ NOT AT END-OF-PAGE ] [ END- WRITE ] |
FORMAT (QSAM)
RECORD-NAME mist be defined via Data Division FD entry.
FROM option yields results identical to:
MOVE identifier TO record-name
WRITE record ?name
- When the ADVANCING clause is omitted automatic line advancing is provided
WRITE . . . . .AFTER ADVANCING 1 LINE.
- A further positioning operand is AFTER / BEFORE ADVANCING PAGE.
ACCEPT identifier
[FROM mnemonic-name]
The ?mnemonic-name? must be associated with a device in the SPECIAL-NAMES paragraph.
When FROM phrase is omitted, SYSIN is the default.
The identifier may be a group or elementary item.
EXAMPLE
77 SEARCH-VALUE PIC X(10).
??????..
PROCEDURE DIVISION.
ACCEPT SEARCH-VALUE FROM SYSIN.
???
ACCEPT Statement
ACCEPT identifier FROM DATE
ACCEPT identifier FROM DAY
ACCEPT identifier FROM DAY-OF-WEEK
ACCEPT identifier FROM TIME
DATE has implicit PICTURE 9(6) (YYMMDD).
DAY has implicit PICTURE 9(5) (YYDDD).
DAY-OF-WEEK has implicit PICTURE 9(1) where the value ?1? represents Monday, ?2? implies Tuesday, etc.
- TIME has implicit PICTURE 9(8) (HHMMSSTH).
01 TODAY.
02 THIS-YEAR PIC 99.
02 THIS-MONTH PIC 99.
02 THIS-DAY PIC 99.
01 CURRENT-DATE.
02 THIS-MONTH PIC Z9.
02 FILLER PIC X VALUE ?/?.
02 THIS-DAY PIC 99.
02 FILLER PIC X VALUE ?/?.
02 THIS-YEAR PIC 99.
PROCEDURE DIVISION.
ACCEPT TODAY FROM DATE
MOVE CORR TODAY TO CURRENT-DATE
___________________________________________________________
DISPLAY STATEMENT
DISPLAY identifier ?1 identifier ?2. . . .
[ UPON mnemonic-name ]
If the identifier is numeric (but not external decimal), the contents are converted to an external format.
When the UPON phrase in omitted, the default device in SYSOUT.
Example
CONFIGURATION SECTION.
SPECIAL-NAMES . SYSOUT IS SYSPRINT.. . . . .
PROCEDURE
DISPLAY SRCH-ARG ? NOT IN TABLE. ?
DISPLAY SRCH-ARG SPACES ? NOT IN TABLE. ?
When a figurative constant is specified, only a single occurance is displayed.
3.5 Conditional Verbs & sequence control verbs
3.5.1 IF Statement
IF EMPNO < PREV-EMPNO
MOVE ?OUT OF ORDER? TO MESSAGE-TXT
PERFORM ERROR-MESSAGE
ADD 1 TO INVALID-COUNTER
ELSE
MOVE EMPNO TO PREV-EMPNO
END-IF.
IF Statement
05 EMPL-STATUS PIC X.88 SECRATARY VALUE ?S?.
88 APPRENTICE VALUE ?A?.
88 WORKER VALUE ?W?.
88 MANAGER VALUE ?M?.
88 NONE-OF-ABOVE VALUE ?N?.
IF SECRETARY
PERFORM ADMIN-PROCESS
________________________________________________________________
05 EMPL-STATUS PIC X.
88 SECRATARY VALUE ?S?.
88 APPRENTICE VALUE ?A?.
88 WORKER VALUE ?W?.
88 MANAGER VALUE ?M?.
88 NONE-OF-ABOVE VALUE ?N?.
IF EMPL-STATUS = ?S?
PERFORM ADMIN-PROCESS
The two techniques for testing are equivalent.
3.5.2 CONTINUE Statement
The CONTINUE statement allows you to specify ?no operation ? where an imperative statement is expected.
Example1 ? ?NEXT SENTENCE ?
IF A = B
IF C = D
NEXT SENTENCE
ELSE
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
ADD C TO TOTAL
IF E = F
MOVE MESSAGE-4 TO RPT-MESSAGE-2
END-IF
END-IF
Control comes here
Next instruction
Example 2 ? ?CONTINUE ?
IF A = B
IF C = D
CONTINUE
ELSE
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
Control comes here
ADD C TO TOTAL
IF E = F
MOVE ERR-MSG TO RPT-ERR-MSG
END-IF
END-IF
Next instruction
3.5.3 EVALUATE Statement
The COBOL II EVALUATE statement provides a technique for coding similarly to the structured design CASE construct.
EVALUATE is an alternative to nested IF?s.
?WHEN? phrase can be written similar to a logic table.
The organization of the EVALUATE STATEMENT IS:
EVALUATE
Identifier
Literal
Expression
True
FALSE
WHEN
Condition
TRUE
FALSE
ANY
Literal
Identifier
Arithmetic expression
Operand(s) before the WHEN phrase is/are called selection subject(s)
Operand(s) within the WHEN phrase is/are called selection subject(s)
The must be the same number of selection subjects as selection objects.
EVALUATE Statement
Examples
EMPLOYEE-REC.
?????.
02 SHIFT PIC X.
88 DAY VALUE ?D?.
88 NIGHT VALUE ?N?.
02 ??????
PROCEDURE DIVISION.
?????????..
EVALUATE TRUE
WHEN DAY PERFORM DAY-PARA
WHEN NIGHT PERFORM NIGHT-PARA
END-EVALUATE
The above EVALUATE could also have been written in either ft the following ways:
EVALUATE SHIFT
WHEN ?D? PERFORM DAY-PARA
WHEN ?N? PERFORM NIGHT-PARA
END-EVALUATE
EVALUATE TRUE
WHEN SHIFT = ?D? DAY-PARA
WHEN SHIFT = ?T? NIGHT-PARA
END-EVALUATE
3.6 Sorting and merging of files
SORTING
In order to update sequential files it is necessary to sort the records. COBOL provides the SORT verb to accomplish this. In this operation, the file to be sorted is input to be sorted and a new file is created in a different sequence. In addition to these 2 files a temporary file is also defined. A file may be sorted either in the ascending or the descending orders of a defined key field.
The format of the SORT statement is :
SORT file-name ON (ASCENDING) KEY data-name1, data-name2,....
(DESCENDING)
[ON (ASCENDING/DESCENDING) KEY data-name3,
data-name4]
USING file-name2 GIVING file-name3.
file-name1 : the sort file defined by an SD description in the DATA DIVISION
Format : SD filename
file-name2 : the file on which the unsorted input records are found
file-name3 : the output file of sorted records
Records may be sorted using either numeric or non-numeric key fields. Ascending sequence used with an alphabetic field will cause sorting from A - Z, and descending sequence will cause sorting from Z - A.
The program below illustrates the SORT statement :
IDENTIFICATION DIVISION.
PROGRAM-ID. PRNT-MKS.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT SORTFILE ASSIGN TO "SORTE.DAT".
SELECT STUDFILE ASSIGN TO "STUDENT.DAT".
SELECT TEMPFILE ASSIGN TO "TEMP.DAT".
DATA DIVISION.
FILE SECTION.
FD STUDFILE
LABEL RECORDS ARE STANDARD.
01 STUDBUF.
05 STUD-NO PIC 9(4).
05 STUD-NAME PIC A(20).
05 ADDRS PIC X(30).
05 DATE-OF-BIRTH PIC 9(6).
FD TEMPFILE
LABEL RECORDS ARE STANDARD.
01 TEMPBUF.
05 T-STUD-NO PIC 9(4).
05 T-STUD-NAME PIC A(20).
05 T-ADDRS PIC X(30).
05 T-DATE-OF-BIRTH PIC 9(6).
SD SORTFILE.
01 SORTBUF.
05 S-STUD-NO PIC 9(4).
05 S-STUD-NAME PIC A(20).
05 S-ADDRS PIC X(30).
05 S-DATE-OF-BIRTH PIC 9(6).
WORKING-STORAGE SECTION.
01 EOF PIC X VALUE "N".
PROCEDURE DIVISION.
MAIN-PARA.
PERFORM SORT-PARA.
PERFORM INIT.
PERFORM PROG-EXEC UNTIL EOF = "Y".
PERFORM TERMIN.
GOBACK.
SORT-PARA.
SORT SORTFILE ON ASCENDING KEY S-STUD-NO
USING STUDFILE GIVING TEMPFILE.
INIT.
OPEN INPUT TEMPFILE.
PROG-EXEC.
READ TEMPFILE AT END MOVE "Y" TO EOF.
IF EOF = "N"
DISPLAY "STUDENT NUMBER : ", T-STUD-NO
DISPLAY "STUDENT NAME : ", T-STUD-NAME
DISPLAY "ADDRESS : ", T-ADDRS
DISPLAY "DATE OF BIRTH : ", T-DATE-OF-BIRTH
STOP " ".
TERMIN.
CLOSE TEMPFILE.
The SORT-FILE is defined with an SD and has no LABEL RECORDS clause.
PROCESSING DATA BEFORE AND/OR AFTER SORTING
Consider the following SORT statement :
SORT SORT-FILE
ON ASCENDING KEY TERR
USING IN-FILE GIVING SORTED-MSTR.
This statement performs the following operations :
1. Opens IN-FILE and SORTED-MSTR.
2. Moves IN-FILE records to the SORT-FILE.
3. Sorts SORT-FILE into ascending sequence by TERR, which is a field defined as part of the SD SORT-FILE record.
4. Moves the sorted SORT-FILE to the output file called SORTED-MSTR.
5. Closes IN-FILE and SORTED-MSTR after all records have been processed.
The SORT statement can however, be used in conjunction with procedures that process records before they are sorted and/or process records after they are sorted.
INPUT PROCEDURE
Here, the SORT statement is used to perform processing of incoming records just before they are sorted. This is accomplished with an INPUT PROCEDURE clause in place of the USING clause. The format is :
SORT file-name1
ASCENDING
ON KEY data-name1.....
DESCENDING
INPUT PROCEDURE IS procedure-name1 THRU procedure name2
USING file-name2 .... THROUGH
The INPUT PROCEDURE processes data from the incoming file prior to sorting.
An INPUT PROCEDURE may be used to perform the following operations prior to sorting : (1) validate data in the input records, (2) eliminate records with blank fields, (3) remove unnecessary fields from the input records, and (4) count input records.
INPUT PROCEDURE CODING RULES
1. The entire program should consist of SECTIONs. Each SECTION is followed by a paragraph-name. The INPUT PROCEDURE of the SORT refers to SECTION-name followed by a paragraph-name.
E.g.
MAIN SECTION.
MAIN-PARA.
SORT WORK-FILE
INPUT PROCEDURE PRIOR-TO-SORT
GIVING SORTED-FILE.
GOBACK.
PRIOR-TO-SORT SECTION.
PRIOR-TO-SORT-MAIN-PARA.
2. In the main paragraph of the section specified in the INPUT PROCEDURE :
a) OPEN the input file.
b) READ an initial record from the input file.
c) PERFORM a paragraph within the INPUT PROCEDURE section that will
process input records, release them to the sort file, and continue to read
records until there is no more data.
d) After all records have been processed CLOSE the input file.
e) In order for the INPUT PROCEDURE to be terminated, the last statement in
the last paragraph of the section must be executed. We must use a GO TO
for branching to the paragraph that contains this last statement.
E.g.
PRIOR-TO-SORT SECTION.
PRIOR-TO-SORT-MAIN-PARA.
OPEN INPUT IN-FILE.
READ IN-FILE AT END MOVE ?N? TO ANS.
PERFORM PROCESS-IN-RECS UNTIL ANS = ?Y?.
CLOSE IN-FILE.
GO TO END-OF-SECTION.
3. At the paragraph within the INPUT PROCEDURE section that processes input records prior to sorting:
a) MOVE input data to the sort record.
b) RELEASE each sort record, which writes the record to the sort file. This
RELEASE makes the record available for sorting. RELEASE ... FROM .... can
be used in place of a MOVE and RELEASE.
c) Continue to read and process input until there is no more data.
E.g.
PROCESS-IN-RECS.
MOVE IN-REC TO SORT-REC.
RELEASE SORT-REC.
READ IN-FILE AT MOVE ?N? TO REPLY.
4. The paragraph located physically at the end of the INPUT PROCEDURE section must be the last one executed. Hence, a GO TO in the section?s main para is required to transfer control to this last paragraph. If no processing is required, code an EXIT statement as the only entry in this last paragraph of the section.
E.g.
MAIN SECTION.
MAIN-PARA.
SORT WORK-FILE
INPUT PROCEDURE PRIOR-TO-SORT GIVING SORTED-FILE.
GOBACK.
PRIOR-TO-SORT SECTION.
PRIOR-TO-SORT-MAIN-PARA.
GO TO END-OF-SECTION.
PROCESS-INP-RECS.
:END-OF-SECTION.
EXIT.
A SORT routine that eliminates records with a quantity field = 0 before sorting.
The test for zero quantity will be performed in an INPUT PROCEDURE.
* SORT with INPUT PROCEDURE
IDENTIFICATION DIVISION.
PROGRAM-ID. SORT-I.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT STUDFILE ASSIGN TO "STUDENT.DAT".
SELECT SORTFILE ASSIGN TO "SORTE.DAT".
SELECT TEMPFILE ASSIGN TO "TEMP.DAT".
DATA DIVISION.
FILE SECTION.
FD STUDFILE
LABEL RECORDS ARE STANDARD.
01 STUDBUF.
05 STUD-NO PIC 9(4).
05 STUD-NAME PIC A(20).
05 ADDRS PIC X(30).
05 DATE-OF-BIRTH PIC 9(6).
FD TEMPFILE
LABEL RECORDS ARE STANDARD.
01 TEMPBUF.
05 T-STUD-NO PIC 9(4).
05 T-STUD-NAME PIC A(20).
05 T-ADDRS PIC X(30).
05 T-DATE-OF-BIRTH PIC 9(6).
SD SORTFILE
01 SORTBUF.
05 S-STUD-NO PIC 9(4).
05 S-STUD-NAME PIC A(20).
05 S-ADDRS PIC X(30).
05 S-DATE-OF-BIRTH PIC 9(6).
WORKING-STORAGE SECTION.
01 EOF PIC X VALUE "N".
PROCEDURE DIVISION.
SORTING SECTION.
MAIN-PARA.
SORT SORTFILE ON ASCENDING KEY S-STUD-NO
INPUT PROCEDURE A-PARA THRU A-EXIT GIVING TEMPFILE.
GOBACK.
A-PARA SECTION.
PARA-1.
PERFORM OPEN-PARA.
PERFORM READ-PARA.
PERFORM CHECK-PARA UNTIL EOF = "Y".
GO TO CLOSE-PARA.
A-EXIT.
EXIT.
OPEN-PARA.
OPEN INPUT STUDFILE.
READ-PARA.
READ STUDFILE AT END MOVE "Y" TO EOF.
IF EOF = "Y"
GO TO A-EXIT.
CHECK-PARA.
MOVE STUDBUF TO SORTBUF.
RELEASE SORTBUF.
PERFORM READ-PARA.
CLOSE-PARA.
CLOSE STUDFILE.
OUTPUT PROCEDURE
An OUTPUT PROCEDURE processes all sorted records in the sort file and handles the transfer of these records to the output file. While in an INPUT PROCEDURE we RELEASE records to a sort file rather than writing them, in an OUTPUT PROCEDURE, we RETURN records from the sort file rather than reading them. The format of the RETURN is as follows :
RETURN sort-file-name1
AT END imperative-statement1.
The format of the OUTPUT PROCEDURE is as below :
DESCENDING
SORT file-name1 ON KEY data-name1 .....
ASCENDING
THRU
OUTPUT PROCEDURE IS procedure-name1 procedure-name1
THROUGH
1. The entire program should consist of sections. The OUTPUT PROCEDURE should refer to a section-name followed by a paragraph-name.
E.g.
MAIN SECTION.
MAIN-PARA.
SORT WORK-FILE USING IN-FILE
OUTPUT PROCEDURE AFTER-SORT.
GOBACK.
AFTER-SORT SECTION.
AFTER-SORT-MAIN-PARA.
2. In the main-para of the section specified in the OUTPUT PROCEDURE :
a) OPEN the output file.
b) RETURN an initial record from the sort file - the RETURN functions like a
READ.
c) PERFORM a paragraph within the section that will process records from
the sort file and continue to process them until there is no more data.
d) After all records have been processed, CLOSE the output file.
e) Code a GO TO, branching to the paragraph located physically at the end of
the section.
E.g.
AFTER-SORT SECTION.
AFTER-SORT-MAIN-PARA
OPEN OUTPUT SORTED-FILE.
RETURN WORK-FILE AT END MOVE ?N? TO REPLY.
PERFORM PROCESS-SORT-RECS UNTIL ANS = ?Y?.
CLOSE SORTED-FILE.
GO TO END-OF-SECTION.
3. At the paragraph that processes sort records after sorting :
a) Perform any operations on work or sort records.
b) Move the sort record to the output area.
c) WRITE each sorted record to the output file.
d) Continue to RETURN sort file records until there is no more data.
E.g.
PROCESS-SORT-RECS.
WRITE SORTED-REC FROM WORK-REC.
RETURN WORK-FILE AT END MOVE ?N? TO REPLY.
4. The paragraph located physically at the end of the OUTPUT PROCEDURE section must be the last one executed. Hence a GO TO in the section?s main-para is required to transfer control to this last paragraph. If no processing is required, code an EXIT statement as the only entry in this last paragraph.
E.g.
MAIN SECTION.
MAIN-PARA.
SORT WORK-FILE USING IN-FILE
OUTPUT PROCEDURE AFTER-SORT.
GOBACK.
AFTER-SORT SECTION.
AFTER-SORT-MAIN-PARA.
:
GO TO END-OF-SECTION.
PROCESS-SORT-RECS.
:
END-OF-SECTION.
EXIT.
Sample program illustrating output procedure
* SORT WITH OUTPUT PROCEDURE
IDENTIFICATION DIVISION.
PROGRAM-ID. SORT-O.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT STUDFILE ASSIGN TO "STUDENT.DAT".
SELECT SORTFILE ASSIGN TO "SORTE.DAT".
SELECT TEMPFILE ASSIGN TO "TEMP.DAT".
DATA DIVISION.
FILE SECTION.
FD STUDFILE
LABEL RECORDS ARE STANDARD.
01 STUDBUF.
05 STUD-NO PIC 9(4).
05 STUD-NAME PIC A(20).
05 ADDRS PIC X(30).
05 DATE-OF-BIRTH PIC 9(6).
FD TEMPFILE
LABEL RECORDS ARE STANDARD.
01 TEMPBUF.
05 T-STUD-NO PIC 9(4).
05 T-STUD-NAME PIC A(20).
05 T-ADDRS PIC X(30).
05 T-DATE-OF-BIRTH PIC 9(6).
SD SORTFILE.
01 SORTBUF.
05 S-STUD-NO PIC 9(4).
05 S-STUD-NAME PIC A(20).
05 S-ADDRS PIC X(30).
05 S-DATE-OF-BIRTH PIC 9(6).
WORKING-STORAGE SECTION.
01 EOF PIC X VALUE "N".
PROCEDURE DIVISION.
SORTING SECTION.
MAIN-PARA.
SORT SORTFILE ON ASCENDING KEY S-STUD-NO
USING STUDFILE
OUTPUT PROCEDURE A-PARA THRU A-EXIT.
GOBACK.
A-PARA SECTION.
PARA-1.
PERFORM OPEN-PARA.
PERFORM READ-PARA .
PERFORM CHECK-PARA UNTIL EOF = "Y".
GO TO CLOSE-PARA.
A-EXIT.
EXIT.
OPEN-PARA.
OPEN OUTPUT TEMPFILE.
READ-PARA.
RETURN SORTFILE AT END MOVE "Y" TO EOF.
CHECK-PARA.
WRITE TEMPBUF FROM SORTBUF.
PERFORM READ-PARA.
CLOSE-PARA.
CLOSE TEMPFILE.
When to use INPUT and/or OUTPUT PROCEDURES
If there are many records that need to be eliminated, it is more efficient to remove them before sorting. In this way, we do not waste computer time numerous records that will later be removed from the sorted file. Thus, in the case where a large number of records will be removed, an INPUT PROCEDURE should be used.
However, in order to eliminate records with blank fields, it is efficient to remove those records after sorting. After sorting, all blank field records will be at the beginning of the file. (A blank is the lowest printable character in a collating sequence and will appear first in a sorted file.) Here, the OUTPUT PROCEDURE should be used.
MERGING
COBOL has a MERGE statement that will combine two or more files into a single file. It?s format is similar to that of SORT.
MERGE file-name1
{ON ASCENDING KEY (data-name1,....)
DESCENDING KEY }
USING file-name2, file-name3,...
GIVING file-name4
The files to be merged must each be in sequence by the key field, and the records in the file to be merged must be of equal length. An output file is created containing all records from the input file in the correct sequence.
File-name1 : the work-file specified as an SD
data-name?n? : the key-field
The MERGE statement automatically handles the opening, closing and READ/WRITE functions associated with files. However, for the MERGE operation to take place, the input files must be in the sorted order.
The program below illustrates the MERGE statement :
IDENTIFICATION DIVISION.
PROGRAM-ID. MERG-PRG.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT FILE1 ASSIGN TO "FILE1.DAT".
SELECT FILE2 ASSIGN TO "FILE2.DAT".
SELECT MERGE-FILE ASSIGN TO "MERGE.DAT".
SELECT OUTPUT-FILE ASSIGN TO "OUT.DAT".
DATA DIVISION.
FILE SECTION.
FD FILE1
LABEL RECORDS ARE STANDARD.
01 FILE1-REC.
02 F-ITEM-NO PIC 9(3).
02 F-AMT PIC 9(4)V99.
FD FILE2
LABEL RECORDS ARE STANDARD.
01 FILE2-REC.
02 G-ITEM-NO PIC 9(3).
02 G-AMT PIC 9(4)V99.
SD MERGE-FILE.
01 MERGE-REC.
02 ITEM-NO PIC 9(3).
02 AMT PIC 9(4)V99.
FD OUTPUT-FILE
LABEL RECORDS ARE STANDARD.
01 OUT-REC.
02 O-ITEM-NO PIC 9(3).
02 O-AMT PIC 9(4)V99.
WORKING-STORAGE SECTION.
77 EOF PIC X VALUE "N".
77 CHOICE PIC X VALUE "Y".
PROCEDURE DIVISION.
MAIN-PARA.
PERFORM OPEN-PARA.
PERFORM ACCEPT-APARA UNTIL CHOICE = "N".
CLOSE FILE1.
MOVE "Y" TO CHOICE.
PERFORM ACCEPT-BPARA UNTIL CHOICE = "N".
CLOSE FILE2.
PERFORM MERG-PARA.
GOBACK.
OPEN OUTPUT FILE1.
OPEN OUTPUT FILE2.
ACCEPT-APARA.
DISPLAY "F-ITEM-NO".
ACCEPT F-ITEM-NO.
DISPLAY "F-AMT".
ACCEPT F-AMT.
WRITE FILE1-REC.
DISPLAY "CONTINUE Y/N".
ACCEPT CHOICE.
ACCEPT-BPARA.
DISPLAY "G-ITEM-NO".
ACCEPT G-ITEM-NO.
DISPLAY "G-AMT".
ACCEPT G-AMT.
WRITE FILE2-REC.
DISPLAY "CONTINUE Y/N".
ACCEPT CHOICE.
MERG-PARA.
MERGE
USING FILE1, FILE2 GIVING OUTPUT-FILE.
3.7 Character handling
3.7.1 Inspect Tallying Statement
The INSPECT statement provides the capability to count (tally) or replace specific characters in a data-item.
INSPECT identifier-1 TALLYING identifier-2
FOR CHARACTERS BEFORE
[INITIAL] identifier-4
INSPECT identifier-1 TALLYING identifier-2
FOR CHARACTERS AFTER
[INITIAL] identifier-4
INSPECT identifier-1 TALLYING identifier-2
FOR ALL identifier-3 | literal
AFTER [INITIAL] identifier-4
INSPECT identifier-1 TALLYING identifier-2
FOR LEADING identifier-3 | literal
AFTER [INITIAL] identifier-4
The inspected item must have USAGE DISPLAY (either elementary or group item).
?identifier-2? must be an elementary numeric item.
Inspection begins at the leftmost character of the inspected item and proceeds byte-by-byte to the rightmost position (except when BEFORE or AFTER used).
3.7.2 Inspect Replacing Statement
The INSPECT statement also provides the capability to replace specific characters in a data-item (must have USAGE DISPLAY).
INSPECT identifier-1 REPLACING CHARACTERS BY identifier-5 [BEFORE | AFTER [INITIAL] identifier-4] |
INSPECT identifier-1 REPLACING ALL | LEADING | FIRST Identifier-3 BY identifier-5 | literal [BEFORE | AFTER [INITIAL] identifier-4] |
When REPLACING CHARACTERS is used, the identifier-5 (or literal) must be one character in length.
EXAMPLES
______________________________________________________
INSPECT DATA1 REPLACING ALL ? ? BY ?0?
INSPECT DATA2 REPLACING FIRST ZERO BY SPACES
INSPECT DATA3 REPLACING CHARACTERS BY ?X?
___________________________________________________________
3.7.3 Inspect Replacing/Converting
The COBOL II INSPECT verb formats REPLACING / CONVERTING operate differently:
INSPECT FIELD1 CONVERTING ?ABC? TO ?XYZ?
Changes ?ABC1234AAA? TO ?XYZ1234XXX?
INSPECT FIELD1 REPLACING ?ABC? TO ?XYZ?
Changes ?ABC1234AAA? TO ?XYZ1234AAA?
This syntax changes only instances of the complete character string.
3.7.4 String Example
The following example takes a 10-digit string of numbers and ?formats? it into the image of a telephone number, e.g.
0806675432 becomes (080) 667-5432
WORKING-STORAGE SECTION.
TELNUMBER.
04 AREACODE PIC 9(3).
04 LOCAL-NO PIC 9(7).
77 FORMATTED-TELNUMBER PIC X(20).
PROCEDURE DIVISION.
????????
STRING
?(? DELIMITED BY SIZE
AREACODE DELIMITED BY SIZE
?)? DELIMITED BY SIZE
LOCAL-NO(1:3) DELIMITED BY SIZE
?_? DELIMITED BY SIZE
LOCAL-NO(4:4) DELIMITED BY SIZE
INTO FORMATTED-TELNUMBER
END-STRING
DISPLAY FORMATTED-TELNUMBER
????
3.7.5 Unstring Statement
UNSTRING identifier-1
[DELIMETED BY [ALL] identifier-2 ]
INTO identifier-4 ????..
[ON OVERFLOW??.]
[NOT ON OVERFLOW???.]
END-UNSTRING
The UNSTRING statement is used to split a single data-item into several data-items.
EXAMPLE
To present an address like this:
ALIT
01 ADDRESS1 PIC X(84) VALUE
?ALIT:ADDRESS2.
05 LINE1 PIC X(80).
05 LINE2 PIC X(80).
05 LINE3 PIC X(80).
UNSTRING ADDRESS1 DELIMITED BY ?;: OR ?\?
INTO LINE1 LINE2 LINE3
END-UNSTRING
3.8 COBOL subroutines
3.8.1 Linkage Section
Example
(Examples of definitions in CALLING program and CALLED program)
3.8.2 Calling Program
DATA DIVISION.
WORKING-STORAGE SECTION.
EMP-DET.
05 EMPNO PIC 9(6).
05 EMPNAME PIC X(15)
05 DEPT PIC 9(5)
????..
?????
PROCEDURE DIVISION.
????.
????.
CALL CALLED-PGM USING EMP-DET. ????.
????.
3.8.3 Called Program
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LINKAGE SECTION.
EMP-INFO.
05 EMPNUM PIC 9(6).
05 EMPNAME PIC X(15)
05 DEPTNO PIC 9(5)
PROCEDURE DIVISION USING EMP-INFO.
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