PROCEDURE DIVISION.
Begin.
MERGE WorkFile ON ASCENDING KEY ProductCode-WF
USING UlsterSales, ConnachtSales, MunsterSales, LeinsterSales
OUTPUT PROCEDURE IS SummarizeProductSales
STOP RUN.
SummarizeProductSales.
OPEN OUTPUT SummaryFile
RETURN WorkFile
AT END SET EndOfWorkfile TO TRUE
END-RETURN
PERFORM UNTIL EndOfWorkFile
MOVE ZEROS TO TotalSalesValue
MOVE ProductCode-WF TO ProductCode-SF
PERFORM UNTIL ProductCode-WF NOT EQUAL TO ProductCode-SF
ADD ValueOfSale-WF TO TotalSalesValue
RETURN WorkFile
AT END SET EndOfWorkfile TO TRUE
END-RETURN
END-PERFORM
WRITE SummaryRec
END-PERFORM
CLOSE SummaryFile.
Every month, the TrueValue head office receives a file from its branch in each of the four provinces of Ireland.
Each file records the sales made in that province. A program is required that will combine these four files and, from them, produce a summary file that records the total value of the sales of each product sold by the company. The summary file must be ordered on ascending ProductCode. The record description for each of the four files is as follows:
Field
Type Length
Value
ProductCode
X
6
–
ValueOfSale
9
6
0–9999.99
The record description for the summary file is shown next:
Field
Type Length
Value
ProductCode
X
6
–
TotalValueOfSale
9
8
0–999999.99
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Chapter 14 ■ Sorting and Merging
Summary
This chapter explored the SORT and MERGE verbs. You discovered how to define the work file that SORT uses as a temporary scratch pad when sorting. You saw how to create an INPUT PROCEDURE to filter or alter the records sent to the work file and how to create an OUTPUT PROCEDURE to get and process the sorted records from the work file. You also learned that you can use the INPUT PROCEDURE and OUTPUT PROCEDURE in concert to achieve interesting results: you can sort a table by using an INPUT PROCEDURE to get the elements from the table and release them to the work file and an OUTPUT PROCEDURE to retrieve the sorted element-records from the work file and place them back in the table. In addition, the ISO 2002 version of COBOL allows you to sort a table directly. Finally, you saw how to use the MERGE verb to combine identically ordered files into one file that preserves the ordering.
The next chapter introduces COBOL string handling. In many other languages, string manipulation is achieved by using a library of string functions. In COBOL, string manipulation uses intrinsic functions, reference modification, and the STRING, UNSTRING, and INSPECT verbs.
prOGraMMING eXerCISe 1
Visitors to an irish web site are asked to fill in a guestbook form. the form requests the name of the visitor, their country of origin, and a comment. these fields are stored as a fixed length record in GuestBookFile.
GuestBookFile is an unordered sequential file, each record of which has the following description:
Field
Type
Length
Value
GuestName
X
20
–
CountryName
X
20
–
GuestComment
X
40
–
You are required to write a program to print a report that shows the number of visitors from each foreign
(non-irish) country. the report must be printed in ascending CountryName sequence. Because the records in
GuestBookFile are not in any particular order, before the report can be printed, the file must be sorted by CountryName. the report template is as follows:
Foreign Guests Report
Country Visitors
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
XXXXXXXXXXXXXXXXXXXX XXXXXX
***** End of report *****
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Chapter 14 ■ Sorting and Merging
prOGraMMING eXerCISe 1: aNSWer
Because only foreign visitors are of interest, there is no point in sorting the entire file. an INPUT PROCEDURE is used to select only the records of visitors from foreign (non-irish) countries. an OUTPUT PROCEDURE is used to create the report.
When you examine the fields of a GuestBookFile record, notice that, for the purposes of this report, GuestName and GuestComment are irrelevant. the only field you need for the report is the CountryName field. So in addition to selecting only foreign guests, the INPUT PROCEDURE alters the structure of the records supplied to the sort process. Because the new records are only 20 characters in size, rather than 80 characters, the amount of data that has to be sorted is substantially reduced.
Listing 14-10. Using an INPUT PROCEDURE to Modify and Filter the Records in the Input File IDENTIFICATION DIVISION.
PROGRAM-ID. Listing14-10.
AUTHOR. Michael Coughlan.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT GuestBookFile
ASSIGN TO "Listing14-10.Dat"
ORGANIZATION IS LINE SEQUENTIAL.
SELECT WorkFile
ASSIGN TO "Work.Tmp".
SELECT ForeignGuestReport
ASSIGN TO "Listing14-10.rpt"
ORGANIZATION IS LINE SEQUENTIAL.
DATA DIVISION.
FILE SECTION.
FD GuestBookFile.
01 GuestRec.
88 EndOfFile VALUE HIGH-VALUES.
02 GuestNameGF PIC X(20).
02 CountryNameGF PIC X(20).
88 CountryIsIreland VALUE "IRELAND".
02 GuestCommentGF PIC X(40).
SD WorkFile.
01 WorkRec.
88 EndOfWorkFile VALUE HIGH-VALUES.
02 CountryNameWF PIC X(20).
FD ForeignGuestReport.
01 PrintLine PIC X(38).
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Chapter 14 ■ Sorting and Merging
WORKING-STORAGE SECTION.
01 Heading1 PIC X(25)
VALUE " Foreign Guests Report".
01 Heading2.
02 FILLER PIC X(22) VALUE "Country".
02 FILLER PIC X(8) VALUE "Visitors".
01 CountryLine.
02 PrnCountryName PIC X(20).
02 PrnVisitorCount PIC BBBZZ,ZZ9.
01 ReportFooting PIC X(27)
VALUE " ***** End of report *****".
01 VisitorCount PIC 9(5).
PROCEDURE DIVISION.
Begin.
SORT WorkFile ON ASCENDING CountryNameWF
INPUT PROCEDURE IS SelectForeignGuests
OUTPUT PROCEDURE IS PrintGuestsReport.
STOP RUN.
PrintGuestsReport.
OPEN OUTPUT ForeignGuestReport
WRITE PrintLine FROM Heading1
AFTER ADVANCING PAGE
WRITE PrintLine FROM Heading2
AFTER ADVANCING 1 LINES
RETURN WorkFile
AT END SET EndOfWorkfile TO TRUE
END-RETURN
PERFORM PrintReportBody UNTIL EndOfWorkfile
<
br /> WRITE PrintLine FROM ReportFooting
AFTER ADVANCING 2 LINES
CLOSE ForeignGuestReport.
PrintReportBody.
MOVE CountryNameWF TO PrnCountryName
MOVE ZEROS TO VisitorCount
PERFORM UNTIL CountryNameWF NOT EQUAL TO PrnCountryName
ADD 1 TO VisitorCount
RETURN WorkFile
AT END SET EndOfWorkfile TO TRUE
END-RETURN
END-PERFORM
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Chapter 14 ■ Sorting and Merging
MOVE VisitorCount TO PrnVisitorCount
WRITE PrintLine FROM CountryLine
AFTER ADVANCING 1 LINE.
SelectForeignGuests.
OPEN INPUT GuestBookFile.
READ GuestBookFile
AT END SET EndOfFile TO TRUE
END-READ
PERFORM UNTIL EndOfFile
IF NOT CountryIsIreland
MOVE CountryNameGF TO CountryNameWF
RELEASE WorkRec
END-IF
READ GuestBookFile
AT END SET EndOfFile TO TRUE
END-READ
END-PERFORM
CLOSE GuestBookFile.
359
Chapter 15
String Manipulation
In many languages, string manipulation is achieved by using a library of string functions or, as in Java, the methods of a String class. COBOL also uses a library of string-manipulation functions, but most string manipulation is done using reference modification and the three string-handling verbs: STRING, UNSTRING, and INSPECT.
This chapter starts by examining the string-handling verbs. These verbs allow you to count and replace
characters, and concatenate and split strings. You are then introduced to reference modification, which lets you treat any string as an array of characters. Finally, you learn about the intrinsic functions used for string and date manipulation.
The INSPECT Verb
The INSPECT verb has four formats;
• The first format is used for counting characters in a string.
• The second replaces a group of characters in a string with another group of characters.
• The third combines both operations in one statement.
• The fourth format converts each character in a set of characters to its corresponding character
in another set of characters.
Before starting a formal examination of the INSPECT formats, let’s get a feel for how the verb operates by looking at a short program (see Listing 15-1). The program accepts a line of text from the user and then counts and displays how many times each letter of the alphabet occurs in the text.
Listing 15-1. Finding the Number of Times Each Letter Occurs in a Line of Text
IDENTIFICATION DIVISION.
PROGRAM-ID. Listing15-1.
AUTHOR. Michael Coughlan.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 TextLine PIC X(80).
01 LowerCase PIC X(26) VALUE "abcdefghijklmnopqrstuvwxyz".
01 UpperCase VALUE "ABCDEFGHIJKLMNOPQRSTUVWXYZ".
02 Letter PIC X OCCURS 26 TIMES.
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Chapter 15 ■ String Manipulation
01 idx PIC 99.
01 LetterCount PIC 99
01 PrnLetterCount PIC Z9.
PROCEDURE DIVISION.
Begin.
DISPLAY "Enter text : " WITH NO ADVANCING
ACCEPT TextLine
INSPECT TextLine
CONVERTING LowerCase TO UpperCase
PERFORM VARYING idx FROM 1 BY 1 UNTIL idx > 26
MOVE ZEROS TO LetterCount
INSPECT TextLine TALLYING LetterCount FOR ALL Letter(idx)
IF LetterCount > ZERO
MOVE LetterCount TO PrnLetterCount
DISPLAY "Letter " Letter(idx) " occurs " PrnLetterCount " times"
END-IF
END-PERFORM
STOP RUN.
The program gets a line of text from the user. It then uses INSPECT..CONVERTING to convert all the characters to their uppercase equivalents.
The UpperCase data item in this program does double duty. It is used in INSPECT CONVERTING as an ordinary
alphanumeric data item, but it is also defined as a 26-element prefilled table of letters. Using this table, the PERFORM
loop supplies the letters one at a time to INSPECT..TALLYING, which counts the number of times each letter occurs in TextLine. It stores the count in LetterCount. If the letter occurred in TextLine, then the count is displayed.
There are some interesting things to note about this program. First, since intrinsic functions were introduced in the ANS 85 version of COBOL, is it no longer necessary to use INSPECT.. CONVERTING to convert characters to uppercase. Nowadays you can use the UPPER-CASE function. This function has the added benefit that it can do the conversion without changing the original text. Second, you don’t actually need to hold the letters of the alphabet as a table. Reference modification allows you to treat any alphanumeric data item as a table of characters. Listing 15-2
shows a version of the program that incorporates these modernizations.
Listing 15-2. Modernized Version of the Program in Listing 15-1
IDENTIFICATION DIVISION.
PROGRAM-ID. Listing15-2.
AUTHOR. Michael Coughlan.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 TextLine PIC X(80).
01 Letters PIC X(26) VALUE "ABCDEFGHIJKLMNOPQRSTUVWXYZ".
01 LetterPos PIC 99.
01 LetterCount PIC 99.
01 PrnLetterCount PIC Z9.
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Chapter 15 ■ String Manipulation
PROCEDURE DIVISION.
Begin.
DISPLAY "Enter text : " WITH NO ADVANCING
ACCEPT TextLine
PERFORM VARYING LetterPos FROM 1 BY 1 UNTIL LetterPos > 26
MOVE ZEROS TO LetterCount
INSPECT FUNCTION UPPER-CASE(TextLine)
TALLYING LetterCount FOR ALL Letters(LetterPos:1)
IF LetterCount > ZERO
MOVE LetterCount TO PrnLetterCount
DISPLAY "Letter " Letters(LetterPos:1) " occurs " PrnLetterCount " times"
END-IF
END-PERFORM
STOP RUN.
INSPECT .. TALLYING: Format 1
INSPECT..TALLYING counts the number of occurrences of a character in a string. The metalanguage for this version of INSPECT is given in Figure 15-1.
Figure 15-1. Metalanguage for INSPECT..TALLYING
This version of INSPECT works by scanning the source string SourceStr$i from left to right, counting the
occurrences of all characters or just a specified character:
• The behavior of INSPECT is modified by the LEADING, ALL, BEFORE, and AFTER phrases. An ALL,
LEADING, or CHARACTERS phrase may only be followed by one BEFORE and one AFTER phrase.
• As indicated by the ellipsis after the final bracket, you can use a number of counters—each
with its own modifying phrases—with an INSPECT..TALLYING statement.
• If Compare$il or Delim$il is a figurative constant, it is one character in size.
Modifying Phrases
The operation of INSPECT is governed by the modifying phrases used. The meaning of these phrases is as follows: BEFORE: Designates the characters to the left of the associated delimiter (Delim$il) as valid.
If the delimiter is not present in SourceStr$i, then using the BEFORE phrase implies that all
the characters are valid.
AFTER: Designates the characters to the right of the associated delimiter (Delim$il) as valid.
If the delimiter is not present in the SourceStr$i, then using the AFTER phrase implies that
there are no valid characters in the string.
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Chapter 15 ■ String Manipulation
ALL: Counts all Compare$il characters
from the first matching valid character to the first
invalid one.
LEADING: Counts leading Compare$il characters from the first matching valid character
encountered to the first nonmatching or invalid character.
INSPECT .. TALLYING Examples
Example 15-1 shows some example INSPECT statements, and Listing 15-3 presents a small program. The program’s task is to count the number of vowels and the number of consonants in a line of text entered by the user.
Example 15-1. Some INSPECT..TALLYING Example Statements
INSPECT TextLine TALLYING UnstrPtr FOR LEADING SPACES.
INSPECT TextLine TALLYING
eCount FOR ALL "e" AFTER INITIAL "start"
BEFORE INITIAL "end".
INSPECT TextLine TALLYING
aCount FOR ALL "a"
eCount FOR ALL "e"
oCount FOR ALL "o"
INSPECT FUNCTION REVERSE(TextLine) TALLYING
TrailingSpaces FOR LEADING SPACES
COMPUTE StrLength = FUNCTION LENGTH(TextLine) - TrailingSpaces
Listing 15-3. Counting Vowels and Consonants
IDENTIFICATION DIVISION.
PROGRAM-ID. Listing15-3.
AUTHOR. Michael Coughlan.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 TextLine PIC X(80).
01 VowelCount PIC 99 VALUE ZERO.
01 ConsonantCount PIC 99 VALUE ZERO.
PROCEDURE DIVISION.
Begin.
DISPLAY "Enter text : " WITH NO ADVANCING
ACCEPT TextLine
INSPECT FUNCTION UPPER-CASE(TextLine) TALLYING
VowelCount FOR ALL "A" "E" "I" "O" "U"
ConsonantCount FOR ALL
"B" "C" "D" "F" "G" "H" "J" "K" "L" "M" "N" "P"
"Q" "R" "S" "T" "V" "W" "X" "Y" "Z"
DISPLAY "The line contains " VowelCount " vowels and "
ConsonantCount " consonants."
STOP RUN.
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Chapter 15 ■ String Manipulation
Programmatic Detour
There are a number of ways to solve the problem of finding the number of vowels and consonants in a line of text.
Michael Coughlan Page 44
