COBOL Bank Ledger System

A COBOL bank ledger system demonstrating classic mainframe-style banking. This system simulates a bank teller workstation.

• Account Management: Create new accounts with complete customer information
• Account Information: View account details with integrated transaction history
• Deposits & Withdrawals: Process monetary transactions with balance updates
• Transfers: Move funds between accounts
• Transaction History: Complete audit trail with dates, descriptions, and amounts

• Data Persistence: Indexed files for accounts, sequential files for transactions
• Sample Data: Pre-populated with 5 accounts and realistic transaction history
• Easy Reset: Single command to reset database to baseline state
• Error Handling: Clear status messages for all operations

1. Install Homebrew (if not already installed):

   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

2. Install GnuCOBOL:

   brew install gnu-cobol

3. Verify installation:

   cobc --version

GnuCOBOL may require additional libraries:

brew install gmp berkeley-db

ledger-cobol/
├── src/               # Main COBOL source files
│   └── BANKLED.cob    # Main program with all functionality
├── copybooks/         # Reusable data structures
│   ├── ACCOUNT.cpy    # Account record definition
│   ├── TRANS.cpy      # Transaction record definition
│   └── COMMON.cpy     # Common constants and messages
├── data/              # Data files (created on first run)
│   ├── accounts.dat   # Indexed account master file
│   └── trans.dat      # Sequential transaction log
├── scripts/           # Utility scripts
│   └── reset-db.sh    # Database reset script
├── bin/               # Compiled executables (created on build)
├── Makefile           # Build system

1. Build the application:

   make build

2. Reset database with sample data:

   make reset

3. Run the application:

   make run

The system presents a traditional mainframe-style menu interface:

1. Create New Account - Add new customer accounts

   • Enter customer details (name, address, phone)
   • Choose account type (Checking/Savings)
   • Automatically assigns next available account number

2. Account Information - View comprehensive account details

   • Select account from numbered list
   • Displays account holder information
   • Shows current balance in highlighted box
   • Lists transaction history with dates and descriptions

3. Deposit - Add funds to account

   • Select account using intuitive interface
   • Enter deposit amount
   • Updates balance immediately

4. Withdrawal - Remove funds from account

   • Select account with validation
   • Ensures sufficient funds before processing
   • Updates balance and logs transaction

5. Transfer - Move funds between accounts

   • Clear prompts for source account (FROM)
   • Separate prompt for destination account (TO)
   • Displays comprehensive summary with both account balances

6. Exit - Close application safely

make build      # Compile the application
make clean      # Remove build artifacts
make debug      # Build with debug information

make run        # Run the application
make reset      # Reset database to baseline with sample data
make init-data  # Initialize empty data files

make test       # Run unit tests
make check-deps # Verify GnuCOBOL installation

1. File Status Errors

   • Status 22: Usually indicates duplicate key or file attribute mismatch
   • Status 39: File attribute mismatch between create and read
   • Solution: Run make reset to ensure consistent file structures

2. Berkeley DB Warnings

   • "unexpected file type or format" warnings are normal
   • The application handles these gracefully

3. Account Creation Issues

   • New accounts start at 1000000006 (after the 5 sample accounts)
   • Ensure you run make reset if you get duplicate key errors

• Uses GnuCOBOL's free format (-free flag)
• Follows COBOL 2014 standard
• Traditional COBOL programming patterns with modern enhancements
• All business logic contained in single source file for simplicity
• Copybooks provide shared data structures
• No external dependencies beyond GnuCOBOL runtime

Feel free to submit issues or pull requests to improve the system.

This project is licensed under the MIT License - see the LICENSE file for details.