COBOL Calculator Collection 🧮

A collection of calculators written in COBOL, demonstrating different computational paradigms and modern features like emoji support.

Overview

This project contains three different calculator implementations:

1. Basic Calculator - Traditional infix notation calculator
2. RPN Calculator - Reverse Polish Notation calculator with stack-based evaluation
3. Emoji RPN Calculator - Modern RPN calculator using emoji operators (➕➖✖➗)

Prerequisites

macOS Setup

Install GNU COBOL (GnuCOBOL) via Homebrew:

brew install gnu-cobol

This will install:

• cobc - COBOL compiler
• Required dependencies (berkeley-db, gmp, json-c)

Other Platforms

• Linux: Install gnucobol or open-cobol via your package manager
• Windows: Install GnuCOBOL from the official website

Project Structure

.
├── README.md                    # This file
├── calculator.cob               # Basic infix calculator
├── rpn-calculator.cob          # RPN calculator
├── emoji-rpn-calculator.cob    # Emoji RPN calculator
├── test-rpn.cob               # Test suite for RPN calculator
├── test-emoji-rpn.cob         # Test suite for emoji RPN calculator
├── run-tests.sh               # Test runner for RPN calculator
├── run-emoji-tests.sh         # Test runner for emoji calculator
└── emoji-test.cob             # Emoji support verification

Quick Start

1. Basic Calculator

Compile and run the traditional calculator:

cobc -x calculator.cob -o calculator
./calculator

Example usage:

==============================
       COBOL CALCULATOR
==============================
Enter first number: 10
Enter operation (+, -, *, /): +
Enter second number: 5
Result: 0000000010.00 + 0000000005.00 = 000000000000015.00

2. RPN Calculator

Compile and run the RPN calculator:

cobc -x rpn-calculator.cob -o rpn-calculator
./rpn-calculator

Example usage:

==============================
    RPN COBOL CALCULATOR
==============================
Enter RPN expression (e.g. 3 4 + or 10 2 /): 
3 4 +
Result: +0000000007.00

3. Emoji RPN Calculator 🎉

Compile and run the emoji calculator:

cobc -x emoji-rpn-calculator.cob -o emoji-rpn-calculator
./emoji-rpn-calculator

Example usage:

========================================
    🧮 EMOJI RPN CALCULATOR 🧮
========================================
Enter RPN expression using emoji operators:
➕ for addition    ➖ for subtraction
✖ for multiply     ➗ for division
Example: 3 4 ➕  or  10 2 ➗
3 4 ➕
Result: +0000000007.00 🎉

Running Tests

RPN Calculator Tests

# Run test suite directly
cobc -x test-rpn.cob -o test-rpn
./test-rpn

# Or use the test runner script
chmod +x run-tests.sh
./run-tests.sh

Emoji RPN Calculator Tests

# Run emoji test suite directly
cobc -x test-emoji-rpn.cob -o test-emoji-rpn
./test-emoji-rpn

# Or use the emoji test runner script
chmod +x run-emoji-tests.sh
./run-emoji-tests.sh

Features

Basic Calculator

• ✅ Four basic operations (+, -, *, /)
• ✅ Decimal number support
• ✅ Division by zero protection
• ✅ Interactive loop

RPN Calculator

• ✅ Stack-based evaluation
• ✅ Complex expression support
• ✅ Space-separated input parsing
• ✅ Error handling for invalid expressions
• ✅ Comprehensive test suite (20 test cases)

Emoji RPN Calculator

• ✅ Modern emoji operators (➕➖✖➗)
• ✅ Unicode support in COBOL
• ✅ Colorful error messages with emojis
• ✅ Success celebrations (🎉)
• ✅ Full test coverage (12 test cases)

RPN Expression Examples

Basic Operations

3 4 ➕       → 7      (3 + 4)
10 3 ➖      → 7      (10 - 3)
4 5 ✖       → 20     (4 * 5)
20 4 ➗      → 5      (20 / 4)

Complex Expressions

15 7 1 1 ➕ ➖ ➗ 3 ✖ 2 1 1 ➕ ➕ ➖  → 5
2 3 ➕ 4 5 ➕ ✖                    → 45  ((2+3) * (4+5))
1 2 ➕ 3 ➕ 4 ➕                    → 10  (((1+2)+3)+4)

Error Handling

Both RPN calculators include comprehensive error handling:

• Division by zero: Error: Division by zero ➗
• Insufficient operands: Error: Need 2 operands for ➕
• Stack overflow: Error: Stack overflow! 💥
• Stack underflow: Error: Stack underflow! ⚠️
• Invalid expressions: Error: Invalid RPN expression! ❌

Technical Details

COBOL Features Demonstrated

• Data structures: Stack implementation using OCCURS clause
• String handling: Token parsing and manipulation
• Control flow: PERFORM loops and conditional logic
• Unicode support: Emoji character handling
• Modular programming: Paragraph-based subroutines
• Error handling: Comprehensive validation and messaging

Compilation Notes

• The emoji calculator generates Unicode encoding warnings during compilation, but functions correctly
• All programs compile successfully with GnuCOBOL 3.2+
• No external dependencies beyond the standard COBOL runtime

Test Coverage

RPN Calculator Tests (20 tests)

• Basic arithmetic operations
• Decimal handling
• Zero operations
• Negative numbers
• Complex expressions
• Error conditions

Emoji RPN Calculator Tests (12 tests)

• All emoji operators
• Complex emoji expressions
• Error conditions with emoji messages
• Unicode character validation

Contributing

To extend the calculators:

1. Add new operations: Extend the PROCESS-TOKEN paragraph
2. Add new tests: Follow the existing test patterns
3. Add new features: Use the modular paragraph structure

License

This project is provided as-is for educational purposes, demonstrating COBOL programming capabilities including modern Unicode support.

Fun Facts

• This demonstrates that COBOL, despite being from 1959, can handle modern Unicode emojis! 🎉
• The emoji calculator is likely one of the first emoji-based calculators written in COBOL
• COBOL's verbosity makes the intent very clear, even 65+ years later
• The stack-based RPN implementation showcases COBOL's data structure capabilities

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Built with ❤️ and lots of COBOL verbosity