Understanding NUMVAL in COBOL

COBOL, short for Common Business-Oriented Language, is a programming language that has been widely used in business and financial applications for decades. One of the essential aspects of COBOL programming is working with data, particularly numeric data. In this article, we will delve deep into the concept of NUMVAL in COBOL – what it is, how it is used, and we’ll provide numerous examples to illustrate its functionality.

What is NUMVAL?

NUMVAL is a COBOL intrinsic function that is used to convert a string representation of a number into its equivalent numeric value. In other words, it is used to convert a character string containing digits into a numeric data item that can be used for arithmetic operations or comparisons. The result of the NUMVAL function is a numeric value that can be assigned to a numeric data item in your COBOL program.

The general syntax of the NUMVAL function is as follows:

NUMVAL (source-string, numeric-data-item [, STATUS])

• source-string: This is the character string that contains the numeric value you want to convert.
• numeric-data-item: This is the target numeric data item that will hold the converted numeric value.
• STATUS: An optional parameter that specifies the result of the conversion. It can take on values like NUMVAL_OK, NUMVAL_ERR, etc.

How is NUMVAL Used?

NUMVAL is primarily used when you need to convert user input or external data (often in string format) into a format that can be processed and manipulated as numeric data within your COBOL program. This is particularly common when dealing with file processing or when accepting user input in the form of strings, such as account numbers, transaction amounts, or other numerical values.

By using NUMVAL, you can ensure that the input data is correctly interpreted as a numeric value, allowing you to perform arithmetic operations, comparisons, and other calculations without errors.

Let’s explore some practical examples to understand how NUMVAL works and how it can be used in COBOL programs.

Example 1: Simple Conversion

IDENTIFICATION DIVISION.
PROGRAM-ID. NumvalExample.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 Source-String        PIC X(10) VALUE '12345'.
01 Numeric-Value        PIC 9(5).

PROCEDURE DIVISION.
    MOVE Source-String TO Numeric-Value
    DISPLAY 'Numeric Value: ' Numeric-Value
    STOP RUN.

In this example, we have a simple COBOL program that demonstrates the use of NUMVAL for converting a character string to a numeric value. The program defines a Source-String containing the value ‘12345’ and a Numeric-Value data item. The MOVE statement uses the NUMVAL function to convert the Source-String into a numeric value and stores it in the Numeric-Value data item. The DISPLAY statement then outputs the converted numeric value.

Example 2: Handling Conversion Errors

IDENTIFICATION DIVISION.
PROGRAM-ID. NumvalErrorExample.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 Source-String        PIC X(10) VALUE '12A34'.
01 Numeric-Value        PIC 9(5).
01 Conversion-Status    PIC X(10).

PROCEDURE DIVISION.
    MOVE 'NUMVAL_ERR' TO Conversion-Status
    MOVE Source-String TO Numeric-Value
    NUMVAL (Source-String, Numeric-Value, Conversion-Status)
    IF Conversion-Status = 'NUMVAL_OK'
        DISPLAY 'Numeric Value: ' Numeric-Value
    ELSE
        DISPLAY 'Conversion Error'
    END-IF
    STOP RUN.

In this example, we intentionally provide a non-numeric character (‘A’) in the Source-String to demonstrate how to handle conversion errors using the NUMVAL function. The Conversion-Status data item is used to capture the status of the conversion. If the conversion is successful, the program displays the converted numeric value. If the conversion fails, it displays a “Conversion Error” message.

Example 3: Processing Numeric Data from External Source

IDENTIFICATION DIVISION.
PROGRAM-ID. NumvalExternalData.

DATA DIVISION.
FILE SECTION.
01 Input-File            FILE STATUS IS Input-Status.
02 Input-Record          PIC X(20).

WORKING-STORAGE SECTION.
01 Numeric-Value         PIC 9(5).
01 Conversion-Status     PIC X(10).
01 Input-Status          PIC 9.

PROCEDURE DIVISION.
    OPEN INPUT Input-File
    PERFORM UNTIL Input-Status = 10
        READ Input-File INTO Input-Record
        IF Input-Status = 0
            MOVE 'NUMVAL_ERR' TO Conversion-Status
            MOVE Input-Record TO Numeric-Value
            NUMVAL (Input-Record, Numeric-Value, Conversion-Status)
            IF Conversion-Status = 'NUMVAL_OK'
                DISPLAY 'Numeric Value: ' Numeric-Value
            ELSE
                DISPLAY 'Conversion Error'
            END-IF
        END-IF
    END-PERFORM
    CLOSE Input-File
    STOP RUN.

In this example, we demonstrate how NUMVAL can be used to process numeric data from an external file. The program reads records from an input file and attempts to convert each record using the NUMVAL function. If the conversion is successful, the program displays the converted numeric value. If not, it displays a “Conversion Error” message.

Conclusion

In the world of COBOL programming, the NUMVAL function plays a crucial role in converting character strings containing numeric data into usable numeric values. This is essential for performing calculations, making comparisons, and processing external data sources accurately. By understanding the NUMVAL function and its usage, COBOL programmers can ensure that their programs handle numeric data effectively and with precision.

Throughout this article, we explored the concept of NUMVAL in COBOL, its syntax, and its practical applications. We examined various examples to illustrate how NUMVAL can be used in different scenarios, such as simple conversions, handling conversion errors, and processing numeric data from external sources. Armed with this knowledge, COBOL developers can confidently utilize the NUMVAL function to enhance the accuracy and reliability of their programs, particularly when dealing with numeric data.