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COBOL Tutorial

COBOL IF Statement Quick Reference

The IF statement is COBOL's primary conditional construct, enabling decision-making based on conditions. It evaluates whether a condition is true or false and executes the appropriate code path.

Basic Syntax

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*> Simple IF statement
IF condition
   statement-1
   statement-2
END-IF
 
*> IF with ELSE
IF condition
   statements (when true)
ELSE
   statements (when false)
END-IF
 
*> Multiple conditions with logical operators
IF condition-1 AND condition-2
   statements
ELSE
   statements
END-IF

Comparison Operators

Equality Operators
  • = or EQUAL TO - Equal
  • NOT = or NOT EQUAL TO - Not equal
Inequality Operators
  • > or GREATER THAN - Greater than
  • < or LESS THAN - Less than
  • >= - Greater than or equal
  • <= - Less than or equal

Logical Operators

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*> AND - both conditions must be true
IF field-1 > 0 AND field-2 NOT = SPACES
   PERFORM PROCESS-DATA
END-IF
 
*> OR - either condition can be true
IF department = "IT" OR department = "ENGINEERING"
   MOVE "TECH" TO category
END-IF
 
*> NOT - negates the condition
IF NOT end-of-file
   PERFORM READ-NEXT-RECORD
END-IF
 
*> Complex combinations with parentheses
IF (salary > 50000 AND years > 5) OR (rating = "EXCELLENT")
   PERFORM AWARD-BONUS
END-IF

Practical Examples

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IDENTIFICATION DIVISION.
PROGRAM-ID. IF-EXAMPLES.
DATA DIVISION.
WORKING-STORAGE SECTION.
01  WS-AMOUNT      PIC 9(5)V99 VALUE 1234.56.
01  WS-RATE        PIC 9V999 VALUE 0.15.
01  WS-DISCOUNT    PIC 9(5)V99.
01  WS-CUSTOMER    PIC X(20).
    88  VIP-CUSTOMER VALUE "PREMIUM", "GOLD".
01  WS-QUANTITY     PIC 9(3) VALUE 50.
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    *> Simple comparison
    IF WS-AMOUNT > 1000
       COMPUTE WS-DISCOUNT = WS-AMOUNT * WS-RATE
       DISPLAY "Discount applied: " WS-DISCOUNT
    END-IF
    
    *> IF-ELSE structure
    IF VIP-CUSTOMER
       DISPLAY "VIP customer - special treatment"
       COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.20
    ELSE
       DISPLAY "Regular customer"
       COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.10
    END-IF
    
    *> Nested IF statements
    IF WS-QUANTITY > 100
       IF VIP-CUSTOMER
          COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.30
       ELSE
          COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.15
       END-IF
    ELSE
       IF VIP-CUSTOMER
          COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.20
       ELSE
          COMPUTE WS-DISCOUNT = WS-AMOUNT * 0.10
       END-IF
    END-IF
    
    *> Multiple conditions with logical operators
    IF WS-AMOUNT > 1000 AND WS-QUANTITY > 50
       DISPLAY "Bulk order discount eligible"
    ELSE
       IF WS-AMOUNT > 500 OR VIP-CUSTOMER
          DISPLAY "Standard discount eligible"
       END-IF
    END-IF
    
    STOP RUN.

Common Patterns

Best Practices

  • Always use END-IF to explicitly terminate IF statements for clarity
  • Indent nested IF statements consistently to show hierarchy
  • Use condition names (88-level items) instead of literal comparisons when possible
  • Limit nesting to 3-4 levels deep; use EVALUATE for complex multi-way branches
  • Use parentheses to group complex logical expressions
  • Place most likely or most critical conditions first for performance

Key Takeaways

  • IF statements provide conditional execution based on true/false conditions
  • Use END-IF to explicitly terminate IF blocks, especially with nested structures
  • Combine conditions using AND, OR, and NOT logical operators
  • Comparisons use =, >, <, >=, <=, or NOT = operators
  • Nested IF statements allow for complex multi-level decision logic
  • Consider using EVALUATE for multi-way branches with discrete values

Explain It Like I'm 5 Years Old:

Think of an IF statement like making decisions! If you're deciding whether to play outside, you might say "IF it's sunny outside, THEN I'll go play in the park, ELSE I'll stay inside and read." Just like that, COBOL programs use IF to make choices. The program checks if something is true (like sunny weather) and does one thing, or if it's false (rainy) and does something different. It's like the computer asking questions and doing different things based on the answers!

Related Concepts

Conditional Logic

Decision-making and branching in programs

Logical Operators

AND, OR, NOT operators for complex conditions

Control Flow

Program flow control and execution paths