COBOL - Data Types

In programming languages, a data type or simply a type is an attribute of data which is used to explain the compiler or interpreter how the programmer intends to use the data. Every programming language must have data types. So, data types are used to define the type of variables used in a program.

In COBOL program, data division defines the variables used in the program. You must understand the following terms to describe data in the COBOL. Let's see the following terms:

Data Name
Level Number
Picture Clause
Value Clause

Level Number

A level number defines in which position or level, we can define a data in the record.

Level Number	Description
01	Record description Entry
02 to 49	Group and Elementary Items
66	Rename Clause Items
77	Items which cannot be sub-divided
88	Condition name entry

Elementary Items

Elementary items are the indivisible items. An elementary item contains a level number, picture clause, data name, and value clause (optional).

Group Items

It is a set of one or more elementary items. A group item contains a level number, data name, and value clause (optional). The level number for group items is always 01.

Example:

      DATA DIVISION.
           WORKING-STORAGE SECTION.
           01 WS-NAME    PIC X(25).                               ---> ELEMENTARY ITEM 
           01 WS-CLASS   PIC 9(2)  VALUE  '10'.                   ---> ELEMENTARY ITEM

        01 WS-ADDRESS.                                         ---> GROUP ITEM   
           05 WS-HOUSE-NUMBER    PIC 9(3).                     ---> ELEMENTARY ITEM
           05 WS-STREET          PIC X(15).                    ---> ELEMENTARY ITEM
           05 WS-CITY            PIC X(15).                    ---> ELEMENTARY ITEM
           05 WS-COUNTRY         PIC X(15)  VALUE 'INDIA'.     ---> ELEMENTARY ITEM

Data Name

In the data division section, data names must be specified before they are used in the procedure division.

Data names must have a name specified by the user; the reserved words cannot be used. Data names refer to the memory locations where the actual data is stored. There can be elementary items or group items.

Example:

Valid:
   WS-NAME
   TOTAL-STUDENTS
   A100
   100B

Invalid:
   MOVE               (Reserved Words)
   COMPUTE         (Reserved Words)
   100                  (No Alphabet)
   100+B              (+ is not allowed) 

Picture Clause

Picture Clause defines the following items:

Data Type: It may be of any type like numeric, alphanumeric, or alphabetic.

Data Type	Description
Numeric	0 to 9
Alphabetic	A to Z/a-z
Alpha-numeric	A-Z/a-z/0-9

Sign: With numeric data, this can be used. It can either be - or +.

Decimal Point Position: With numerical data, this can be used. The assumed decimal point enables the decimal values to store the period or dot (.).

Length: Length is used to describe the amount of bytes that the data item will use.

Symbol	Description
9	Numeric. Maximum Length of Numeric data type is 18.
A	Alphabetic. The maximum length of the alphabetic data type is 255.
X	Alphanumeric The maximum length of the Alphanumeric data type is 255.
S	Sign
P	Assumed Decimal

Example:

Let's see one example to show the PIC Clause:

	   IDENTIFICATION DIVISION.
           PROGRAM-ID. HELLO.

       DATA DIVISION.
           WORKING-STORAGE SECTION.
           01 WS-NUM1 PIC S9(3)V9(2).
           01 WS-NUM2 PIC PPP999.
           01 WS-NUM3 PIC S9(3)V9(2) VALUE -123.45.
           01 WS-NAME PIC A(6) VALUE 'Nikita'.
           01 WS-ID PIC X(5) VALUE 'N001'.

       PROCEDURE DIVISION.
           DISPLAY "WS-NUM1 : "WS-NUM1.
           DISPLAY "WS-NUM2 : "WS-NUM2.
           DISPLAY "WS-NUM3 : "WS-NUM3.
           DISPLAY "WS-NAME : "WS-NAME.
           DISPLAY "WS-ID : "WS-ID.
       STOP RUN.

Output:

Value Clause

The value clause is an optional clause for initializing data objects. The values may be numeric literal, figurative constant, or alphanumeric literal. The value clause can be used with elementary items as well as group items.

Example:

Let's see the example for VALUE Clause:

       IDENTIFICATION DIVISION.
           PROGRAM-ID. HELLO.

       DATA DIVISION.
           WORKING-STORAGE SECTION.
           01 WS-NUM1 PIC 99V9 VALUE IS 2.4.
           01 WS-NAME PIC A(6) VALUE 'JTP'.
           01 WS-ID PIC 99 VALUE ZERO.

       PROCEDURE DIVISION.
           DISPLAY "WS-NUM1 : "WS-NUM1.
           DISPLAY "WS-NAME : "WS-NAME.
           DISPLAY "WS-ID   : "WS-ID.
       STOP RUN.

Output:

Data type definitions for COBOL

In the following table, we are explaining the data type definitions and their descriptions for COBOL:

Data type	Description	COBOL
INT2	It is used to specify a 2-byte signed integer.	PIC S9(4) USAGE IS BINARY
INT4	It is used to specify a 4-byte signed integer.	PIC S9(9) USAGE IS BINARY
FLOAT4	It is used to specify a 4-byte single-precision floating-point number.	COMP-1
FLOAT8	It is used to specify an 8-byte double-precision floating-point number.	COMP-2
FLOAT16	It is used to specify a 16-byte extended-precision floating-point number.	Not available
COMPLEX8	It is used to specify a short floating-point complex hex number: an 8-byte complex number, whose real and imaginary parts are each 4-byte single-precision floating-point numbers.	Not available
COMPLEX16	It is used to specify a long floating-point complex hex number: a 16-byte complex number, whose real and imaginary parts are each 8-byte double-precision floating-point numbers.	Not available
COMPLEX32	It is used to specify an extended floating-point hex number: a 32-byte complex number, whose real and imaginary parts are each 16-byte extended-precision floating-point numbers.	Not available
POINTER	It is used to specify a platform-dependent address pointer.	USAGE IS POINTER
CHARn	It is used to specify a string (character array) of length n.	PIC X(n)