ATM Management System

A comprehensive ATM management system implemented in C that allows users to manage bank accounts with various features including account creation, transactions, and account management.

Features

Core Functionality

• ✅ User registration and login with duplicate name checking
• ✅ Create new accounts (savings, current, fixed-term)
• ✅ View all accounts for a user
• ✅ Check detailed account information with interest calculations
• ✅ Make transactions (deposit/withdraw) with validation
• ✅ Update account information (country/phone)
• ✅ Remove existing accounts with confirmation
• ✅ Transfer account ownership between users
• ✅ Comprehensive input validation and error handling

Security Features

• Password input masking during login/registration
• User authentication and authorization
• Account ownership validation
• Input sanitization and validation

Getting Started

Prerequisites

• GCC compiler
• Make utility
• Git (for cloning)

Installation

1. Clone the repository:

git clone https://learn.zone01kisumu.ke/git/oumouma/atm-management-system

2. Navigate to the project directory:

cd atm-management-system

3. Compile the project:

make clean
make

4. Run the application:

./atm

File Structure

.
├── data/
│   ├── users.txt      # User credentials storage
│   └── records.txt    # Account records storage
├── src/
│   ├── main.c         # Main program and menu system
│   ├── auth.c         # Authentication functions
│   ├── system.c       # Core system functions
│   └── header.h       # Function declarations and structures
├── Makefile           # Build configuration
├── test_atm.sh        # Testing guidance script
├── test_interest.c    # Interest calculation verification
└── README.md          # This file

Usage

Once the application is running, you'll see a menu-driven interface. Follow the on-screen prompts to:

1. Register a new user account or Login with existing credentials
2. Create new bank accounts (savings, current, fixed-term)
3. View all your accounts or check detailed account information
4. Make transactions (deposit/withdraw)
5. Update account information
6. Remove accounts or transfer ownership

Default Test Users

• Alice: password q1w2e3r4t5y6
• Michel: password q1w2e3r4t5y6

Account Types and Interest Rates

• Savings: 7% annual interest (calculated monthly: balance × 0.07 ÷ 12)
• Current: No interest
• Fixed01: 4% annual interest (1 year term: balance × 0.04)
• Fixed02: 5% annual interest (2 year term: balance × 0.05 × 2)
• Fixed03: 8% annual interest (3 year term: balance × 0.08 × 3)

Interest Payment Schedule

• Savings: Monthly on the deposit day
• Fixed accounts: Lump sum on maturity date
• Current: No interest

Transaction Rules

• Savings/Current accounts: Allow deposits and withdrawals
• Fixed accounts: No transactions allowed (deposits/withdrawals blocked)
• Withdrawal validation: Cannot withdraw more than available balance
• Amount validation: All amounts must be positive

Data Format

users.txt

id name password
0 Alice q1w2e3r4t5y6
1 Michel q1w2e3r4t5y6

records.txt

id userId userName accountId date country phone balance accountType
0 0 Alice 834213 10/10/2012 UK 291231392 1001.20 saving

Testing

Automated Interest Calculation Test

gcc test_interest.c -o test_interest && ./test_interest

Manual Testing Guide

./test_atm.sh

Audit Test Cases

The system passes all audit requirements including:

1. User registration with duplicate checking
2. Account creation with proper validation
3. Interest calculations matching expected values:
   • Saving account ($1001.20): $5.84 monthly interest
   • Fixed01 account ($1001.20): $40.05 total interest
   • Fixed02 account ($1001.20): $100.12 total interest
   • Fixed03 account ($1001.20): $240.29 total interest
4. Transaction restrictions on fixed accounts
5. Account removal and ownership transfer

Implementation Details

Key Functions

• checkAccountDetails(): View account with interest calculations
• makeTransaction(): Handle deposits/withdrawals with validation
• updateAccountInfo(): Update country/phone with file persistence
• removeAccount(): Delete account with confirmation
• transferOwnership(): Transfer account to another user
• calculateInterest(): Compute interest based on account type

Error Handling

• File I/O error checking
• Input validation for all user inputs
• Account existence verification
• User ownership validation
• Transaction amount validation

License

This project is for educational purposes as part of the Zone01 curriculum.