COBOL Tutorial

COBOL SIGNED-SHORT Clause - Quick Reference

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Overview

The SIGNED-SHORT clause is used to define small signed integer data types in COBOL. It provides memory-efficient storage for applications requiring limited positive and negative values, making it ideal for embedded systems, small counters, and memory-constrained environments.

Purpose and Usage

Memory efficiency - Optimize memory usage for small values
Limited range - Handle small signed integer values
Embedded systems - Support memory-constrained environments
Small counters - Efficient storage for counters and flags
Status codes - Handle small status and error numbers

Syntax

The SIGNED-SHORT clause is used in the DATA DIVISION for small signed integer data definition.

Basic Syntax

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* Basic SIGNED-SHORT syntax
01 data-name PIC S9(n) SIGNED-SHORT.
 
* Complete example with small signed integer types
IDENTIFICATION DIVISION.
PROGRAM-ID. SIGNED-SHORT-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* Small signed integer for temperature readings
01  TEMPERATURE-VALUE    PIC S9(3) SIGNED-SHORT.
* Small signed integer for status codes
01  STATUS-CODE          PIC S9(3) SIGNED-SHORT.
* Small signed integer for small counters
01  SMALL-COUNTER        PIC S9(4) SIGNED-SHORT.
* Small signed integer for error numbers
01  ERROR-NUMBER         PIC S9(3) SIGNED-SHORT.
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Assign small values within SIGNED-SHORT range
    MOVE 25 TO TEMPERATURE-VALUE
    MOVE -5 TO STATUS-CODE
    MOVE 1000 TO SMALL-COUNTER
    MOVE -127 TO ERROR-NUMBER
    
    DISPLAY "Temperature: " TEMPERATURE-VALUE "°C"
    DISPLAY "Status code: " STATUS-CODE
    DISPLAY "Small counter: " SMALL-COUNTER
    DISPLAY "Error number: " ERROR-NUMBER
    STOP RUN.

SIGNED-SHORT provides memory-efficient storage for small signed integer values with limited range.

Practical Examples

Examples of using the SIGNED-SHORT clause in different scenarios with detailed explanations.

Embedded System - Temperature Monitoring

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* Embedded system using SIGNED-SHORT for temperature monitoring
DATA DIVISION.
WORKING-STORAGE SECTION.
* Temperature readings (range: -128 to +127 degrees Celsius)
01  CURRENT-TEMPERATURE  PIC S9(3) SIGNED-SHORT.
* Temperature change (range: -128 to +127 degrees)
01  TEMP-CHANGE          PIC S9(3) SIGNED-SHORT.
* Status indicator (range: -128 to +127)
01  SYSTEM-STATUS        PIC S9(3) SIGNED-SHORT.
* Error code (range: -128 to +127)
01  ERROR-CODE           PIC S9(3) SIGNED-SHORT.
* Retry counter (range: -128 to +127)
01  RETRY-COUNTER        PIC S9(3) SIGNED-SHORT.
 
PROCEDURE DIVISION.
MONITOR-TEMPERATURE.
    * Initialize temperature reading
    MOVE 22 TO CURRENT-TEMPERATURE
    DISPLAY "Current temperature: " CURRENT-TEMPERATURE "°C"
    
    * Record temperature change (negative for cooling)
    MOVE -3 TO TEMP-CHANGE
    ADD TEMP-CHANGE TO CURRENT-TEMPERATURE
    DISPLAY "Temperature after change: " CURRENT-TEMPERATURE "°C"
    
    * Set system status (positive for normal, negative for issues)
    MOVE 1 TO SYSTEM-STATUS
    DISPLAY "System status: " SYSTEM-STATUS
    
    * Handle error condition (negative error codes)
    MOVE -5 TO ERROR-CODE
    DISPLAY "Error code: " ERROR-CODE
    
    * Initialize retry counter
    MOVE 3 TO RETRY-COUNTER
    DISPLAY "Retry counter: " RETRY-COUNTER
    
    * Decrement retry counter
    SUBTRACT 1 FROM RETRY-COUNTER
    DISPLAY "Remaining retries: " RETRY-COUNTER
    
    * Check for extreme temperatures
    IF CURRENT-TEMPERATURE > 100 OR CURRENT-TEMPERATURE < -50
        MOVE -1 TO SYSTEM-STATUS
        DISPLAY "WARNING: Extreme temperature detected!"
    END-IF.

This example demonstrates how SIGNED-SHORT optimizes memory usage in embedded systems for temperature monitoring. Temperature readings, changes, status codes, error codes, and retry counters all use small signed integers within the range of -128 to +127. This provides memory efficiency while handling both positive and negative values for various system states.

Game Development - Score and Status Tracking

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* Game development using SIGNED-SHORT for score and status tracking
DATA DIVISION.
WORKING-STORAGE SECTION.
* Player score (range: -128 to +127 points)
01  PLAYER-SCORE         PIC S9(3) SIGNED-SHORT.
* Health points (range: -128 to +127)
01  HEALTH-POINTS        PIC S9(3) SIGNED-SHORT.
* Level number (range: -128 to +127)
01  LEVEL-NUMBER         PIC S9(3) SIGNED-SHORT.
* Lives remaining (range: -128 to +127)
01  LIVES-REMAINING      PIC S9(3) SIGNED-SHORT.
* Power-up status (range: -128 to +127)
01  POWER-UP-STATUS      PIC S9(3) SIGNED-SHORT.
 
PROCEDURE DIVISION.
TRACK-GAME-STATUS.
    * Initialize player score
    MOVE 0 TO PLAYER-SCORE
    DISPLAY "Initial score: " PLAYER-SCORE
    
    * Add points for successful action
    MOVE 10 TO POWER-UP-STATUS
    ADD POWER-UP-STATUS TO PLAYER-SCORE
    DISPLAY "Score after bonus: " PLAYER-SCORE
    
    * Set health points (can be negative for damage)
    MOVE 100 TO HEALTH-POINTS
    DISPLAY "Health points: " HEALTH-POINTS
    
    * Apply damage (negative value)
    MOVE -20 TO POWER-UP-STATUS
    ADD POWER-UP-STATUS TO HEALTH-POINTS
    DISPLAY "Health after damage: " HEALTH-POINTS
    
    * Set level number
    MOVE 5 TO LEVEL-NUMBER
    DISPLAY "Current level: " LEVEL-NUMBER
    
    * Set lives remaining
    MOVE 3 TO LIVES-REMAINING
    DISPLAY "Lives remaining: " LIVES-REMAINING
    
    * Lose a life
    SUBTRACT 1 FROM LIVES-REMAINING
    DISPLAY "Lives after loss: " LIVES-REMAINING
    
    * Check for game over condition
    IF LIVES-REMAINING <= 0
        MOVE -1 TO POWER-UP-STATUS
        DISPLAY "GAME OVER!"
    END-IF
    
    * Check for health warning
    IF HEALTH-POINTS < 20
        MOVE -2 TO POWER-UP-STATUS
        DISPLAY "WARNING: Low health!"
    END-IF.

This example shows how SIGNED-SHORT efficiently handles game state variables in a memory-constrained environment. Player scores, health points, level numbers, lives remaining, and power-up status all use small signed integers. Negative values represent damage, penalties, or special conditions, while positive values represent bonuses, health, or normal states.

Industrial Control - Sensor Status Monitoring

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* Industrial control system using SIGNED-SHORT for sensor monitoring
DATA DIVISION.
WORKING-STORAGE SECTION.
* Pressure reading (range: -128 to +127 PSI)
01  PRESSURE-READING     PIC S9(3) SIGNED-SHORT.
* Flow rate (range: -128 to +127 GPM)
01  FLOW-RATE            PIC S9(3) SIGNED-SHORT.
* Valve position (range: -128 to +127 degrees)
01  VALVE-POSITION       PIC S9(3) SIGNED-SHORT.
* Alarm status (range: -128 to +127)
01  ALARM-STATUS         PIC S9(3) SIGNED-SHORT.
* Maintenance counter (range: -128 to +127)
01  MAINTENANCE-COUNTER  PIC S9(3) SIGNED-SHORT.
 
PROCEDURE DIVISION.
MONITOR-INDUSTRIAL-SYSTEM.
    * Read pressure sensor
    MOVE 75 TO PRESSURE-READING
    DISPLAY "Pressure: " PRESSURE-READING " PSI"
    
    * Read flow rate (negative for reverse flow)
    MOVE 25 TO FLOW-RATE
    DISPLAY "Flow rate: " FLOW-RATE " GPM"
    
    * Set valve position (negative for closed, positive for open)
    MOVE 90 TO VALVE-POSITION
    DISPLAY "Valve position: " VALVE-POSITION " degrees"
    
    * Initialize alarm status (0 = normal, negative = warnings, positive = errors)
    MOVE 0 TO ALARM-STATUS
    DISPLAY "Alarm status: " ALARM-STATUS
    
    * Set maintenance counter
    MOVE 30 TO MAINTENANCE-COUNTER
    DISPLAY "Days until maintenance: " MAINTENANCE-COUNTER
    
    * Decrement maintenance counter
    SUBTRACT 1 FROM MAINTENANCE-COUNTER
    DISPLAY "Days until maintenance: " MAINTENANCE-COUNTER
    
    * Check for high pressure alarm
    IF PRESSURE-READING > 100
        MOVE -1 TO ALARM-STATUS
        DISPLAY "WARNING: High pressure detected!"
    END-IF
    
    * Check for reverse flow
    IF FLOW-RATE < 0
        MOVE -2 TO ALARM-STATUS
        DISPLAY "WARNING: Reverse flow detected!"
    END-IF
    
    * Check for maintenance due
    IF MAINTENANCE-COUNTER <= 0
        MOVE 1 TO ALARM-STATUS
        DISPLAY "ALERT: Maintenance required!"
    END-IF.

This example demonstrates SIGNED-SHORT usage in industrial control systems for monitoring various sensors and equipment status. Pressure readings, flow rates, valve positions, alarm status, and maintenance counters all use small signed integers. Negative values represent warnings, reverse flow, or closed positions, while positive values represent normal operation, forward flow, or open positions.

Best Practices

Understanding best practices ensures effective use of the SIGNED-SHORT clause.

Best Practices

Use for small values - Use SIGNED-SHORT only for values within its range
Consider memory constraints - Choose SIGNED-SHORT for memory-constrained environments
Validate value ranges - Check that values fit within SIGNED-SHORT limits
Monitor overflow - Watch for potential overflow conditions
Document limitations - Document the limited range of SIGNED-SHORT

Test Your Knowledge

1. What is the primary purpose of the SIGNED-SHORT clause in COBOL?

To sign documents
To define small signed integer data types
To sign programs
To sign files

2. In which COBOL division is the SIGNED-SHORT clause typically used?

IDENTIFICATION DIVISION
ENVIRONMENT DIVISION
DATA DIVISION
PROCEDURE DIVISION

3. What is the difference between SIGNED-SHORT and SIGNED-INT?

They are the same thing
SIGNED-SHORT handles smaller values than SIGNED-INT
SIGNED-SHORT is faster than SIGNED-INT
SIGNED-SHORT is obsolete, SIGNED-INT is modern

4. Can SIGNED-SHORT be used with all numeric data types?

Yes, with all numeric types
No, only with small integer types
No, only with decimal types
Only with specific data types

5. What is the relationship between SIGNED-SHORT and memory usage?

They are unrelated
SIGNED-SHORT uses less memory than larger integer types
SIGNED-SHORT uses more memory than larger integer types
SIGNED-SHORT has no impact on memory

COBOL Tutorial

COBOL SIGNED-SHORT Clause - Quick Reference

Overview

Purpose and Usage

Syntax

Basic Syntax

Practical Examples

Embedded System - Temperature Monitoring

Game Development - Score and Status Tracking

Industrial Control - Sensor Status Monitoring

Best Practices

Best Practices

Test Your Knowledge

Frequently Asked Questions

Related Concepts

Data Types

Memory Management

Embedded Systems

Related Pages

COBOL Tutorial

COBOL SIGNED-SHORT Clause - Quick Reference

Overview

Purpose and Usage

Syntax

Basic Syntax

Practical Examples

Embedded System - Temperature Monitoring

Game Development - Score and Status Tracking

Industrial Control - Sensor Status Monitoring

Best Practices

Best Practices

Test Your Knowledge

Frequently Asked Questions

What is the difference between SIGNED-SHORT and other signed data definitions?

How do you implement the SIGNED-SHORT clause in a COBOL program?

What are some common use cases for the SIGNED-SHORT clause?

How does the SIGNED-SHORT clause affect program performance and memory usage?

Related Concepts

Data Types

Memory Management

Embedded Systems

Related Pages