SOLUTIONS TO REVIEW QUESTIONS for S&S Chapter 4

SOLUTIONS TO REVIEW QUESTIONS: Chapter 4

I. True-False Questions

1.   T
2.   T
3.   T
4.   T
5.   T
6.   F ARE-THERE-MORE-RECORDS would be defined in the WORKING- STORAGE SECTION.
7.   T While this approach is correct, it can lead to confusion. It is better to use values whose meaning is obvious, such as those used in the chapter.
8.   T
9.   T
10. T

II. General Questions

1.

Entry

Division

Purpose

a.

DATE-COMPILED

IDENTIFICATION

Indicates the date of the compilation.

b.

WORKING-STORAGE SECTION

DATA

Defines and describes all fields not part of input or output files.

c.

paragraph-name

IDENTIFICATION or

PROCEDURE

or ENVIRONMENT

Defines a separate group of ENVIRONMENT statements or sentences; same as a module or routine in the PROCEDURE DIVISION.

d.

CONFIGURATION SECTION

ENVIRONMENT

Indicates source and object computer.

e.

FD

DATA

Describes a file.

f.

level numbers

DATA

Used to indicate the hierarchy of data within a record.

g.

LABEL RECORDS

DATA

Indicates whether a file will have header and trailer labels.

h.

FILE SECTION

DATA

Includes a description of all input and output files.

i.

SELECT

ENVIRONMENT

Defines a file and assigns it to a specific device.

j.

AUTHOR

IDENTIFICATION

Indicates the programmer’s name

k.

STOP RUN

PROCEDURE

Terminates the program.

l.

AT END clause

PROCEDURE

Indicates what is to be done when there are no more input records to read.

m.

VALUE

DATA

Initializes a data field in WORKING-STORAGE.

n.

PICTURE

DATA

Indicates the size and type of data in a field.

o.

FILE-CONTROL

ENVIRONMENT

Describes the files and devices to be used.

p.

OPEN

PROCEDURE

Opens input and output files and activates them for processing.

2. The SELECT statement assigns the device to the file used in the READ statement.

3. To activate and deactivate the device on which the files are located.

4. When we want fields to have initial values.

5.     a. Valid
        b. Invalid         MOVE is a reserved word.
        c. Valid
        d. Invalid         Special characters (%) are not permitted in paragraph names.

6. The AT END clause is required whenever reading a sequential file. The computer must be told what to do when there are no more records to process. The NOT AT END clause allows the programmer to specify what should be done when a record is successfully read.

III. Interpreting Instruction Formats

1. Incorrect. Only one file may be specified in a READ.

2. Incorrect. The OPEN statement must specify if a particular file is to be used for input or output. Also, the word AND is not permitted.

3. Incorrect. The AT END clause is used with the READ statement.

4. Correct.

5. Incorrect. The CLOSE does not specify whether a file was used for input or output.

SOLUTIONS TO DEBUGGING EXERCISES

1. The OPEN statement does not indicate which file is input and which is output. The statement should be:
OPEN INPUT SALES-FILE
OUTPUT PRINT-FILE

2. The MOVE statement can only move fields, not files. The statement should be:
MOVE SALES-RECORD TO PRINT-RECORD

3. The WRITE statement must specify a record rather than a file. The statement should be:
WRITE PRINT-RECORD

4. The logic error is in paragraph 200-PROCESS-RTN. The MOVE and WRITE statements are executed even when the READ statement detects that there are no more input records. In COBOL 85 the routine could be coded:
                200-PROCESS-RTN.
                        READ SALES-FILE
                                AT END
                                        MOVE ’NO ’ TO ARE-THERE-MORE-RECORDS
                                NOT AT END
                                        MOVE SALES-RECORD TO PRINT-RECORD
                                        WRITE PRINT-RECORD
                        END-READ.

5. No. Commas are optional in a COBOL program.

6. SALES-FILE was assigned to a device using the SELECT statement in the ENVIRONMENT DIVISION.

7. Yes, this would cause an error because the file is being processed sequentially. The computer must be told what to do when the end of file is reached.

8. Paragraph-names must end with a period.

	*Entry*	*Division*	*Purpose*
a.	DATE-COMPILED	IDENTIFICATION	Indicates the date of the compilation.
b.	WORKING-STORAGE SECTION	DATA	Defines and describes all fields not part of input or output files.
c.	paragraph-name	IDENTIFICATION or PROCEDURE or ENVIRONMENT	Defines a separate group of ENVIRONMENT statements or sentences; same as a module or routine in the PROCEDURE DIVISION.
d.	CONFIGURATION SECTION	ENVIRONMENT	Indicates source and object computer.
e.	FD	DATA	Describes a file.
f.	level numbers	DATA	Used to indicate the hierarchy of data within a record.
g.	LABEL RECORDS	DATA	Indicates whether a file will have header and trailer labels.
h.	FILE SECTION	DATA	Includes a description of all input and output files.
i.	SELECT	ENVIRONMENT	Defines a file and assigns it to a specific device.
j.	AUTHOR	IDENTIFICATION	Indicates the programmer’s name
k.	STOP RUN	PROCEDURE	Terminates the program.
l.	AT END clause	PROCEDURE	Indicates what is to be done when there are no more input records to read.
m.	VALUE	DATA	Initializes a data field in WORKING-STORAGE.
n.	PICTURE	DATA	Indicates the size and type of data in a field.
o.	FILE-CONTROL	ENVIRONMENT	Describes the files and devices to be used.
p.	OPEN	PROCEDURE	Opens input and output files and activates them for processing.