💳 Bank Management System (C)

A console-based banking system built in C demonstrating file handling, structured data management, and core systems programming concepts.

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📌 Overview

This project is a fully functional Bank Management System implemented in C. It simulates real-world banking operations using binary file storage for persistent data management.

The system allows users to create accounts, authenticate, and perform essential banking operations such as deposits, withdrawals, and account management through a clean, color-coded, menu-driven interface.

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⚙️ Core Concepts Demonstrated

• Structures (struct): For robust user data modeling.
• Pointers: For efficient data manipulation and passing references.
• Binary File Handling: Utilizing fread, fwrite, and fseek for persistent storage.
• In-place Record Updates: Modifying specific user balances directly in the file using file positioning (SEEK_CUR, SEEK_SET).
• Modular Design: Function-based architecture separating authentication, transactions, and UI.
• String Handling: Utilizing <string.h> functions like strcmp and strcpy.
• Basic Authentication: Account number and password verification loop.

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🚀 Features

👤 User Management

• Register New Accounts: Generates a new user profile with a starting balance of 0.00.
• Secure Login: Authenticates using the generated account number and password.
• Delete Account: Completely removes user records from the system.

💰 Banking Operations

• Deposit Funds: Safely adds to the current balance.
• Withdraw Funds: Subtracts from the balance (includes insufficient funds validation).
• Balance Inquiry: Displays current account standing and details.

⚙️ Account Settings

• Change Password: Updates the user's credentials in real-time.

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🧠 Implementation Highlights

• Persistent Storage: Uses a binary file (Password_records.txt) to ensure data remains intact between program executions.
• Direct Modification: Implements fseek() to overwrite existing data blocks without rewriting the entire file, ensuring efficiency during deposits and withdrawals.
• Safe Deletion: Ensures data consistency by migrating active accounts to a temporary file (Temp_records.txt), deleting the original file, and renaming the temp file.
• Continuous Interaction: Loop-based menu system (while(1)) keeps the application running until the user explicitly exits.

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🖥️ Interface

• Command Line Interface (CLI): Fully menu-driven for ease of use.
• ANSI Color Coding: Utilizes terminal escape codes (Red, Green, Turquoise, Orange) to distinguish titles, inputs, errors, and success messages.
• Structured Navigation:
  • Main Menu (Login / Register / Exit)
  • Submenu (Banking Operations)
  • Account Settings (Security / Deletion)

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⚠️ Limitations & Future Scope

• Plain Text Security: Passwords are stored in plain text within the binary file (no encryption/hashing applied).
• Hardcoded Limits: Fixed user limit set in memory (MAX_USERS = 100).
• Concurrency: Single-user system intended for local execution (no multi-threading or race-condition handling).
• Platform-Dependent Code: Uses system("cls") for screen clearing, which requires a minor manual adjustment for Unix-based systems (see below).

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🔧 How to Run

Prerequisites

You need a C compiler (like GCC) installed on your system.

OS Specific Setup

The code clears the console screen for a cleaner UI. By default, it uses the Windows command.

• For Windows: No changes needed.
• For Linux / macOS: Open bank.c, scroll to the bottom, and update the clear_screen() function:

  void clear_screen() {
      // system("cls"); // Comment this out
      system("clear"); // Uncomment this for Unix os
  }