💳 ATM Simulation System in C

Team Name: Classic Four
Project Type: ICS Major Project
Team Members:

• 🧑‍💻 Harsh Chaudhari (B24CM1027)
• 🧑‍💻 Brijesh Thakkar (B24ME1018)
• 🧑‍💻 Suvarn Vijay Patil (B24CS1074)
• 🧑‍💻 Faiz Raise (B24BB1010)

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📘 Project Overview

This project is a simulation of an ATM (Automated Teller Machine) system using C programming. It aims to help users experience and understand basic banking operations such as:

• Cash Withdrawal
• Cash Deposit
• Balance Inquiry
• PIN Change
• Transaction Logging

It also simulates a realistic terminal experience using typewriter-style text display and securely manages data using file handling for persistent storage.

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🎯 Objective

The main objective of this project is to replicate the working of a basic ATM system with:

• User-friendly interaction
• PIN authentication
• File-based storage for balance and PIN
• Logging of all transactions with timestamps

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⚙️ Features

• 🔐 User Authentication

  • 3 attempts for 4-digit PIN entry
  • Default PIN = 0000

• 💸 Cash Withdrawal

  • Balance updated and logged after withdrawal

• 💰 Cash Deposit

  • Deposit any valid amount to account
  • Balance updated and logged

• 🧾 Balance Check

  • Display current balance (read from file)

• 🔄 Change PIN

  • User can change their PIN after confirmation

• 📝 Transaction Logging

  • All transactions (withdrawal, deposit, balance check, PIN change) are logged in transaction_log.txt with timestamp

• 🎞️ Typewriter Text Effect

  • Enhances user experience through a character-by-character printing effect

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📁 File Handling System

The program uses the following files:

File Name	Purpose
balance.txt	Stores the account balance
pin.txt	Stores the 4-digit user PIN
transaction_log.txt	Logs each transaction with details

If any of these files are missing, the system loads default values to ensure smooth functioning.

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🧠 Core C Concepts Used

• Functions and Modular Design
• File Handling
• Strings and Character Arrays
• Loops (while, for)
• Conditional Statements (if-else, switch)
• Error Handling & Input Validation

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🔐 Security Measures

• PIN verification before accessing account
• Max 3 attempts for PIN entry
• All actions logged for accountability and security

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