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[cobol] proofread
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Boris Verkhovskiy
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cobol.md
245
cobol.md
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name: COBOL
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contributors:
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- ["Hyphz", "http://github.com/hyphz/"]
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filename: learn.COB
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filename: learn.cob
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---
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COBOL is a business-oriented language revised multiple times since its original design in 1960. It is claimed to still be used in over 80% of
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organizations.
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COBOL is a business-oriented language revised multiple times since its original design in 1960.
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```cobol
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*COBOL. Coding like it's 1985.
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*COBOL. Coding like it's 1985.
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*Compiles with GnuCOBOL in OpenCobolIDE 4.7.6.
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*COBOL has significant differences between legacy (COBOL-85)
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*and modern (COBOL-2002 and COBOL-2014) versions.
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*Legacy versions require columns 1-6 to be blank (they are used
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@ -26,7 +26,7 @@ organizations.
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*it is still common to use all caps when writing COBOL code.
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*This is what most professional COBOL developers do.
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*COBOL statements end with a period.
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*COBOL code is broken up into 4 divisions.
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*Those divisions, in order, are:
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*IDENTIFICATION DIVISION.
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@ -35,8 +35,9 @@ organizations.
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*PROCEDURE DIVISION.
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*First, we must give our program an ID.
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*Identification division can include other values too,
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*but they are comments only. Program-id is the only one that is mandatory.
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*The IDENTIFICATION DIVISION can include other values too,
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*but they are comments only. PROGRAM-ID is the only one that
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*is mandatory.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. LEARN.
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AUTHOR. JOHN DOE.
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@ -44,149 +45,153 @@ organizations.
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*Let's declare some variables.
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*We do this in the WORKING-STORAGE section within the DATA DIVISION.
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*Each data item (aka variable) starts with a level number,
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*then the name of the item, followed by a picture clause
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*Each data item (aka variable) starts with a level number,
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*then the name of the item, followed by a PICTURE clause
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*describing the type of data that the variable will contain.
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*Almost every COBOL programmer will abbreviate PICTURE as PIC.
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*A is for alphabetic, X is for alphanumeric, and 9 is for numeric.
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*example:
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01 MYNAME PIC xxxxxxxxxx. *> A 10 character string.
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*But counting all those x's can lead to errors,
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*so the above code can, and should
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*be re-written as:
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01 MYNAME PIC X(10).
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01 MYNAME PIC XXXXXXXXXX. *> A 10 character string.
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*But counting all those Xs can lead to errors,
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*so the above code can be re-written as
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01 MYNAME PIC X(10).
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*Here are some more examples:
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01 AGE PIC 9(3). *> A number up to 3 digits.
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01 LAST_NAME PIC X(10). *> A string up to 10 characters.
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*In COBOL, multiple spaces are the same as a single space, so it is common
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*to use multiple spaces to line up your code so that it is easier for other
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*coders to read.
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01 inyear picture s9(7). *> S makes number signed.
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*> Brackets indicate 7 repeats of 9,
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*> ie a 6 digit number (not an array).
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01 AGE PICTURE 9(3). *> A number up to 3 digits.
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01 BIRTH_YEAR PIC S9(7). *> A signed number up to 7 digits.
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01 LAST_NAME PIC X(10). *> A string up to 10 characters.
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*In COBOL, multiple spaces are the same as a single space, so it
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*is common to use multiple spaces to line up your code so that it
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*is easier for other coders to read.
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*Now let's write some code. Here is a simple, Hello World program.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. HELLO.
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DATA DIVISION.
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WORKING-STORAGE SECTION.
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01 THE-MESSAGE PIC X(20).
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PROCEDURE DIVISION.
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DISPLAY "STARTING PROGRAM".
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MOVE "HELLO WORLD" TO THE-MESSAGE.
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DISPLAY THE-MESSAGE.
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STOP RUN.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. HELLO.
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DATA DIVISION.
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WORKING-STORAGE SECTION.
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01 THE-MESSAGE PIC X(20).
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PROCEDURE DIVISION.
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DISPLAY "STARTING PROGRAM".
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MOVE "HELLO WORLD" TO THE-MESSAGE.
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DISPLAY THE-MESSAGE.
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STOP RUN.
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*The above code will output:
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*STARTING PROGRAM
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*HELLO WORLD
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********COBOL can perform math***************
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ADD 1 TO AGE GIVING NEW-AGE.
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SUBTRACT 1 FROM COUNT.
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DIVIDE VAR-1 INTO VAR-2 GIVING VAR-3.
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COMPUTE TOTAL-COUNT = COUNT1 PLUS COUNT2.
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ADD 1 TO AGE GIVING NEW-AGE.
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SUBTRACT 1 FROM COUNT.
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DIVIDE VAR-1 INTO VAR-2 GIVING VAR-3.
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COMPUTE TOTAL-COUNT = COUNT1 PLUS COUNT2.
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*********PERFORM********************
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*The PERFORM keyword allows you to jump to another specified section of the code,
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*and then to return to the next executable
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*statement once the specified section of code is completed.
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*The PERFORM keyword allows you to jump to another specified
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*section of the code, and then to return to the next executable
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*statement once the specified section of code is completed.
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*You must write the full word, PERFORM, you cannot abbreviate it.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. HELLOCOBOL.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. HELLOCOBOL.
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PROCEDURE DIVISION.
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FIRST-PARA.
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DISPLAY 'THIS IS IN FIRST-PARA'.
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*skip SECOND-PARA and perform 3rd & 4th
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*then after performing THIRD-PARA and FOURTH-PARA,
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*return here and continue the program until STOP RUN.
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PERFORM THIRD-PARA THRU FOURTH-PARA.
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SECOND-PARA.
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DISPLAY 'THIS IS IN SECOND-PARA'.
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STOP RUN.
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THIRD-PARA.
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DISPLAY 'THIS IS IN THIRD-PARA'.
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FOURTH-PARA.
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DISPLAY 'THIS IS IN FOURTH-PARA'.
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*When you compile and execute the above program, it produces the
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*following result (note the order):
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*THIS IS IN FIRST-PARA
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*THIS IS IN THIRD-PARA
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*THIS IS IN FOURTH-PARA
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*THIS IS IN SECOND-PARA
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PROCEDURE DIVISION.
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FIRST-PARA.
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DISPLAY 'THIS IS IN FIRST-PARA'.
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PERFORM THIRD-PARA THRU FOURTH-PARA. *>skip second-para and perform 3rd & 4th
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*> then after performing third and fourth,
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*> return here and continue the program until STOP RUN.
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SECOND-PARA.
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DISPLAY 'THIS IS IN SECOND-PARA'.
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STOP RUN.
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THIRD-PARA.
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DISPLAY 'THIS IS IN THIRD-PARA'.
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FOURTH-PARA.
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DISPLAY 'THIS IS IN FOURTH-PARA'.
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*When you compile and execute the above program, it produces the following result:
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THIS IS IN FIRST-PARA
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THIS IS IN THIRD-PARA
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THIS IS IN FOURTH-PARA
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THIS IS IN SECOND-PARA
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**********Combining variables together using STRING ***********
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*Now it is time to learn about two related COBOL verbs: string and unstring.
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*The string verb is used to concatenate, or put together, two or more strings.
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*Unstring is used, not surprisingly, to separate a
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*string into two or more smaller strings.
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*It is important that you remember to use ‘delimited by’ when you
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*are using string or unstring in your program.
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*Now it is time to learn about two related COBOL verbs: STRING and
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*UNSTRING.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. LEARNING.
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ENVIRONMENT DIVISION.
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DATA DIVISION.
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WORKING-STORAGE SECTION.
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01 FULL-NAME PIC X(20).
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01 FIRST-NAME PIC X(13) VALUE "BOB GIBBERISH".
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01 LAST-NAME PIC X(5) VALUE "COBB".
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PROCEDURE DIVISION.
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STRING FIRST-NAME DELIMITED BY SPACE
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" "
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LAST-NAME DELIMITED BY SIZE
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INTO FULL-NAME
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END-STRING.
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DISPLAY "THE FULL NAME IS: "FULL-NAME.
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STOP RUN.
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*The STRING verb is used to concatenate, or put together, two or
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*more strings.
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*UNSTRING is used, not surprisingly, to separate a
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*string into two or more smaller strings.
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*It is important that you remember to use DELIMITED BY when you
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*are using STRING or UNSTRING in your program.
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IDENTIFICATION DIVISION.
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PROGRAM-ID. LEARNING.
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ENVIRONMENT DIVISION.
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DATA DIVISION.
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WORKING-STORAGE SECTION.
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01 FULL-NAME PIC X(20).
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01 FIRST-NAME PIC X(13) VALUE "BOB GIBBERISH".
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01 LAST-NAME PIC X(5) VALUE "COBB".
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PROCEDURE DIVISION.
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STRING FIRST-NAME DELIMITED BY SPACE
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" "
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LAST-NAME DELIMITED BY SIZE
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INTO FULL-NAME
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END-STRING.
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DISPLAY "THE FULL NAME IS: "FULL-NAME.
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STOP RUN.
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*The above code will output:
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THE FULL NAME IS: BOB COBB
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*THE FULL NAME IS: BOB COBB
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*Let’s examine it to see why.
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*Let's examine it to see why.
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*First, we declared all of our variables, including the one that we are creating
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*by the string command, in the DATA DIVISION.
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*First, we declared all of our variables, including the one that
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*we are creating by the string command, in the DATA DIVISION.
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*The action takes place down in the PROCEDURE DIVISION.
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*We start with the STRING keyword and end with END-STRING. In between we
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*list what we want to combine together into the larger, master variable.
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*Here, we are combining FIRST-NAME, a space, and LAST-NAME.
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*The action takes place down in the PROCEDURE DIVISION.
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*We start with the STRING keyword and end with END-STRING. In
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*between we list what we want to combine together into the larger,
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*master variable. Here, we are combining FIRST-NAME, a space, and
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*LAST-NAME.
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*The DELIMITED BY phrase that follows FIRST-NAME and
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*LAST-NAME tells the program how much of each variable we want to capture.
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*DELIMITED BY SPACE tells the program to start at the beginning,
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*and capture the variable until it runs into a space.
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*DELIMITED BY SIZE tells the program to capture the full size of the variable.
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*Since we have DELIMITED BY SPACE after FIRST-NAME, the GIBBERISH part is ignored.
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*To make this clearer, change line 10 in the above code to:
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STRING FIRST-NAME DELIMITED BY SIZE
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*The DELIMITED BY phrase that follows FIRST-NAME and
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*LAST-NAME tells the program how much of each variable we want to
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*capture.
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*DELIMITED BY SPACE tells the program to start at the beginning,
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*and capture the variable until it runs into a space.
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*DELIMITED BY SIZE tells the program to capture the full size of
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*the variable.
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*Since we have DELIMITED BY SPACE after FIRST-NAME, the GIBBERISH
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*part is ignored.
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*To make this clearer, change line 10 in the above code to
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STRING FIRST-NAME DELIMITED BY SIZE
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*and then re-run the program. This time the output is:
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THE FULL NAME IS: BOB GIBBERISH COBB
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*THE FULL NAME IS: BOB GIBBERISH COBB
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```
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## Further reading
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* [GnuCOBOL](https://sourceforge.net/projects/open-cobol/)
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* [GnuCOBOL](https://gnucobol.sourceforge.io/)
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@ -4,7 +4,8 @@ contributors:
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translators:
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- ["GOLGO11", "https://github.com/GOLGO11/"]
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---
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COBOL是一门面向商业的语言，它从1960年最初设计以来被修订过数次。它被宣称仍然有超过80%的机构在使用它。
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COBOL是一门面向商业的语言，它从1960年最初设计以来被修订过数次。
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```cobol
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*COBOL. 最好是按照它1985年的标准来编程。
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@ -179,5 +180,4 @@ COBOL是一门面向商业的语言，它从1960年最初设计以来被修订
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## 想了解更多吗?
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* [GnuCOBOL](https://sourceforge.net/projects/open-cobol/)
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* [GnuCOBOL](https://gnucobol.sourceforge.io/)
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