MainframeMaster

COBOL Condition Names (88-levels)

Condition names (88-levels) create readable boolean conditions over data items, replacing magic values with meaningful names. They improve code clarity and make maintenance easier.

Basic Condition Name Declaration

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       WORKING-STORAGE SECTION.
       01 CUSTOMER-STATUS PIC X VALUE 'A'.
           88 ACTIVE-CUSTOMER    VALUE 'A'.
           88 INACTIVE-CUSTOMER  VALUE 'I'.
           88 SUSPENDED-CUSTOMER VALUE 'S'.
           88 CLOSED-CUSTOMER    VALUE 'C'.

Declare condition names using level 88 under a data item. Each condition name represents a specific value that the data item can have. Use meaningful names that describe the business condition.

Using Condition Names in Logic

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       IF ACTIVE-CUSTOMER
           DISPLAY 'Customer is active'
           PERFORM PROCESS-ACTIVE-CUSTOMER
       ELSE IF INACTIVE-CUSTOMER
           DISPLAY 'Customer is inactive'
           PERFORM PROCESS-INACTIVE-CUSTOMER
       ELSE IF SUSPENDED-CUSTOMER
           DISPLAY 'Customer is suspended'
           PERFORM PROCESS-SUSPENDED-CUSTOMER
       END-IF.

Use condition names directly in IF statements. This is much more readable than testing for 'A', 'I', or 'S' directly. The code becomes self-documenting and easier to understand.

Setting Values with Condition Names

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       *> Set values using condition names
       SET ACTIVE-CUSTOMER TO TRUE
       SET INACTIVE-CUSTOMER TO TRUE
       SET SUSPENDED-CUSTOMER TO TRUE
       
       *> Multiple values for same condition
       01 PROCESSING-CODE PIC X.
           88 VALID-CODES VALUE 'A' 'B' 'C' 'D'.
           88 INVALID-CODES VALUE 'X' 'Y' 'Z'.

Use SET statement to assign values using condition names. You can define multiple values for the same condition name using a list. This centralizes all valid values in one place.

Complex Condition Names

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       01 TRANSACTION-AMOUNT PIC 9(9)V99.
           88 SMALL-TRANSACTION  VALUE 0 THRU 1000.
           88 MEDIUM-TRANSACTION VALUE 1001 THRU 10000.
           88 LARGE-TRANSACTION  VALUE 10001 THRU 999999.
           88 ZERO-AMOUNT        VALUE 0.
           88 POSITIVE-AMOUNT    VALUE 1 THRU 999999.

Define ranges using THRU keyword for numeric conditions. You can create overlapping conditions and use them in complex logic. This makes business rules explicit and maintainable.

Nested Condition Names

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       01 CUSTOMER-RECORD.
           05 CUSTOMER-TYPE PIC X.
               88 INDIVIDUAL VALUE 'I'.
               88 CORPORATE VALUE 'C'.
           05 ACCOUNT-STATUS PIC X.
               88 OPEN-ACCOUNT VALUE 'O'.
               88 CLOSED-ACCOUNT VALUE 'C'.
           05 CREDIT-RATING PIC 9.
               88 EXCELLENT-CREDIT VALUE 9.
               88 GOOD-CREDIT VALUE 7 THRU 8.
               88 FAIR-CREDIT VALUE 5 THRU 6.
               88 POOR-CREDIT VALUE 1 THRU 4.

Create condition names at different levels of a group item. This allows for complex business logic while keeping the code readable. Use meaningful prefixes to distinguish between different types of conditions.

Condition Names in EVALUATE

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       EVALUATE TRUE
           WHEN ACTIVE-CUSTOMER AND INDIVIDUAL
               PERFORM PROCESS-INDIVIDUAL-ACTIVE
           WHEN ACTIVE-CUSTOMER AND CORPORATE
               PERFORM PROCESS-CORPORATE-ACTIVE
           WHEN INACTIVE-CUSTOMER
               PERFORM PROCESS-INACTIVE
           WHEN OTHER
               PERFORM PROCESS-UNKNOWN-STATUS
       END-EVALUATE.

Use condition names in EVALUATE statements for complex decision logic. Combine multiple conditions using AND/OR operators. This makes complex business rules clear and maintainable.

Conditional Logic

IF statements and decision making

Working Storage

Data declaration and initialization