COMP-2 | COMPUTATION-2

COMP-2 is a USAGE type used to store internal double-precision (64 bit) floating-point numbers. COMP-2 allows a VALUE clause with a signed floating-point.

Storage Size and Format -

COMP-2 has no PICTURE clause, and it is 8 bytes long (DOUBLE WORD). COMP-2 data value stored in the format of mantissa and exponent. The mantissa is the numeric value, and the exponent is the precision number. In the 8 bytes, the sign stores in the leftmost first byte, the exponent stores in the next 11 bits, and the mantissa stores in the remaining 52 bits.

Using -

Floating-point numbers are real numbers - For example -, 9.99, 99, etc.

Definition in a COBOL Program -

To define a COMP-2 variable in your COBOL program, we use the USAGE IS COMP-2 clause in the DATA DIVISION. For example -

01 WS-DFPN     USAGE IS COMP-2.

In this example, WS-DFPN is a variable holding a double-precision floating-point number using 8 bytes of storage.

Assigning Values to a COMP-2 Variable -

We can assign values to a COMP-2 variable like any other numeric variable in COBOL. For example -

MOVE 9.999 TO WS-DFPN.

9.999 value stores in a variable that is declared as COMP-2. The data is stored in the memory like .9999 * 10E 1. 9.999 equal to .9999 * 10E 1. In the above, 1 is the exponent value (stored in the leftmost 8 bits), and .9999 is mantissa (stored in the remaining 55 bits).

Arithmetic Operations -

We can perform arithmetic operations (add, subtract, multiply, divide, etc.) on COMP-2 variables just like any other numeric variables. For example -

ADD 10.5 TO WS-DFPN.

Range of Values -

COMP-2 can represent values in the approximate range of ±2.23 x 10^-308 to ±1.80 x 10^308.

Practical Example -

Scenario - Defining and initializing COMP-2 variables and using them for calculations and display.

Code -

----+----1----+----2----+----3----+----4----+----5----+
       IDENTIFICATION DIVISION. 
       PROGRAM-ID. COMP2. 
       AUTHOR. MTH. 

       DATA DIVISION. 
       WORKING-STORAGE SECTION.
       01 WS-VAR.
          05 WS-PI           USAGE IS COMP-2.
          05 WS-RADIUS       USAGE IS COMP-2. 
          05 WS-AREA         USAGE IS COMP-2. 

       PROCEDURE DIVISION. 

           MOVE 3.1415927          TO WS-PI. 
           MOVE 10                 TO WS-RADIUS.  
           COMPUTE WS-AREA = WS-PI * (WS-RADIUS ** 2). 

           DISPLAY "THE AREA OF THE CIRCLE: " WS-AREA.
           STOP RUN.

Output -

THE AREA OF THE CIRCLE:  .31415926999999994E 03