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🪞 Overview

LedgerCore is an Object-Oriented Banking System built entirely in C++, designed to demonstrate real-world software engineering principles — classes, inheritance, encapsulation, and true runtime polymorphism — through a practical, relatable domain: banking. Every account in LedgerCore is created as a specific type — Savings or Current — but managed uniformly through a base Account* pointer. When the monthly cycle runs, each account decides for itself, at runtime, whether to earn interest or pay a fee. 💬 "One interface. Many behaviors. Resolved at runtime."

┌───────────────┐ │ 🏦 Bank │ └───────┬───────┘ ▼ ┌───────────────┐ │ Account* ptr │ └───┬───────┬───┘ ▼ ▼ ┌──────────┐ ┌──────────┐ │ Savings │ │ Current │ │ Account │ │ Account │ └──────────┘ └──────────┘

🔗 Live Demo: ayeshajavid91-star.github.io/LedgerCore

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✨ Feature Matrix

🎯 Feature	📋 Description	⚙️ Implemented With
🧾 Account Creation	Open new customer accounts with unique auto-generated account numbers	Classes & Constructors
💰 Deposit / Withdraw	Fund transfers with real-time balance validation	Encapsulated Methods
📜 Transaction History	Every deposit, withdrawal, and fee is logged per account	Vectors of Transaction Records
🏦 Central Bank Manager	A single Bank class owns and manages every account	Pointers & Aggregation
🔄 Runtime Polymorphism	Interest vs. fee logic resolved dynamically, per account, at runtime	Virtual Functions
📊 Monthly Cycle Engine	One function applies the correct operation across every account type	Abstract Base Class

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🧬 OOP Architecture — Class Hierarchy

classDiagram
    class Account {
        <<abstract>>
        #string accountNumber
        #string ownerName
        #double balance
        #vector~Transaction~ history
        +deposit(amount)
        +withdraw(amount)
        +applyMonthlyOperation()* 
    }

    class SavingsAccount {
        -double interestRate
        -double minBalance
        +applyMonthlyOperation()
        +withdraw(amount)
    }

    class CurrentAccount {
        -double withdrawalFee
        -double maintenanceFee
        +applyMonthlyOperation()
        +withdraw(amount)
    }

    class Bank {
        -vector~Account*~ accounts
        +openAccount()
        +runMonthlyCycle()
        +findAccount(accountNumber)
    }

    Account <|-- SavingsAccount : inherits
    Account <|-- CurrentAccount : inherits
    Bank o-- Account : manages

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🔄 Runtime Polymorphism — How the Magic Happens

🏦 Savings Account	💼 Current Account
Earns monthly compound interest interest = balance × (annualRate / 12) Enforces a minimum balance on withdrawals Rewards long-term saving behavior	Deducts a fixed fee per withdrawal Charges a monthly maintenance fee Built for frequent, transactional use

sequenceDiagram
    participant Bank
    participant Account as Account*
    participant Savings as SavingsAccount
    participant Current as CurrentAccount

    Bank->>Account: runMonthlyCycle()
    Account->>Savings: applyMonthlyOperation()
    Savings-->>Account: + interest applied
    Account->>Current: applyMonthlyOperation()
    Current-->>Account: - fees deducted
    Note over Account: Resolved dynamically at runtime<br/>via virtual dispatch

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Because applyMonthlyOperation() is declared as a pure virtual function in Account, every derived class must supply its own implementation — and the correct version is chosen automatically at runtime, with zero if/else type-checking required. That's polymorphism doing exactly what it's meant to do.

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🛠️ Tech Stack

Layer	Technology	Purpose
⚙️ Core Logic	C++ — Classes, Inheritance, Virtual Functions, Abstract Classes, Pointers, Vectors	Console banking engine
🌐 Web Version	HTML, CSS, JavaScript	Interactive browser demo of the same logic

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⚙️ How It Works

Step	Description
1	Each account is created as a SavingsAccount or CurrentAccount object, but stored and managed through a common Account* pointer inside the Bank class.
2	When withdraw() or applyMonthlyOperation() is called on an account pointer, C++ determines at runtime which derived class's version to execute.
3	Savings accounts calculate interest as balance × (annualRate / 12), added monthly.
4	Current accounts deduct a fixed transaction fee per withdrawal plus a fixed monthly maintenance fee.

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▶️ Getting Started

🚀 Try it Instantly — No Installation

👉 Launch LedgerCore Web Demo 👈

💻 Run the C++ Console Version

# 1️⃣ Clone the repository
git clone https://github.com/ayeshajavid91-star/LedgerCore.git

# 2️⃣ Move into the project folder
cd LedgerCore

# 3️⃣ Compile
g++ LedgerCore.cpp -o LedgerCore

# 4️⃣ Run
./LedgerCore

🖥️ Console Menu

#	Option
1	Open New Account
2	Deposit
3	Withdraw
4	View Account Details
5	View Transaction History
6	View All Accounts
7	Run Monthly Cycle (Interest/Fee)
8	Exit

🌐 Or Run the Web Version Locally

git clone https://github.com/ayeshajavid91-star/LedgerCore.git
cd LedgerCore

Then open index.html in your browser.

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📂 Project Structure

LedgerCore/
│
├── ⚙️  LedgerCore.cpp   → C++ console application (core OOP engine)
├── 🌐 index.html        → Web version (browser demo)
└── 📘 README.md         → You are here

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🏷️ GitHub Topics

cpp oop banking-system polymorphism inheritance console-application

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🗺️ Roadmap

• Core account creation & management
• Deposit / withdraw with validation
• Transaction history tracking
• Runtime polymorphism (Savings vs. Current)
• Monthly cycle engine
• File-based persistence (save/load accounts)
• Admin dashboard for the web version
• Unit tests for interest & fee calculations

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👤 Author

Ayesha Javid

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📄 License

All Rights Reserved.

This project and its source code are the intellectual property of the author. No part of this repository — including the code, design, or documentation — may be copied, modified, distributed, used, or reproduced in any form without the explicit written permission of the author.

© 2026 Ayesha Javid. Unauthorized use is strictly prohibited.

For permissions or licensing inquiries, contact: ayeshajavid91@gmail.com

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