COBOL Tutorial

STANDARD-BINARY - Binary Integers

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When to use binary vs decimal

Use BINARY/COMP for counters, indexes, and flags. Use PACKED-DECIMAL/DISPLAY for currency and precise decimal math.

Typical Declarations and Sizes

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01 I16 PIC S9(4)  BINARY.   *> ~2 bytes
01 I32 PIC S9(9)  BINARY.   *> ~4 bytes
01 I64 PIC S9(18) BINARY.   *> ~8 bytes

Compiler options can influence exact mapping. Check documentation.

Range Guide (Typical)

Digits	Bytes	Signed Range (approx)
1–4	2	-32768 .. 32767
5–9	4	-2,147,483,648 .. 2,147,483,647
10–18	8	~±9.22e18

Signedness and Alignment

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01 COUNT   PIC 9(5)  BINARY.   *> Unsigned
01 OFFSET  PIC S9(5) BINARY.   *> Signed

Alignment affects how fields are placed in memory; aligned fields may be faster to access.

COMP/COMP-5 Notes

COMP often maps to BINARY; COMP-5 may indicate native machine binary sizes without decimal truncation rules (compiler-dependent)
Be explicit with BINARY for clarity

Best Practices and Common Mistakes

Best Practices

Pick the smallest type that safely fits the range
Use decimal types for financial data
Document assumptions when writing binary to external files

Common Mistakes

Mistake	Problem	Fix
Using BINARY for money	Rounding/inexact values	Use PACKED-DECIMAL
Overflow	Negative wrap/abend	Use a wider type; validate inputs

Quick Reference

Usage	Meaning	Example
BINARY	Binary integer	PIC S9(9) BINARY
COMP	Compiler-mapped binary	PIC 9(4) COMP
COMP-5	Native binary (compiler-specific)	PIC S9(9) COMP-5

Test Your Knowledge

1. Which usages indicate binary integers?

DISPLAY
BINARY/COMP
PACKED-DECIMAL
NATIONAL

2. Best for money?

BINARY
PACKED-DECIMAL
FLOAT
NATIONAL

3. Why alignment matters?

Affects performance/storage
Affects color
Affects screen size
No reason

Frequently Asked Questions

Related Concepts

PACKED-DECIMAL

Exact decimal storage.

DATA TYPES

Overview of numeric types.

PACKED-DECIMAL

SKIP3 STANDARD-DECIMAL