Encapsulation best practices in C++ - Mini Project: Build & Apply

Encapsulation Best Practices in C++

📖 Scenario: You are creating a simple program to manage a bank account. You want to keep the account balance safe and only allow changes through specific actions like deposits and withdrawals.

🎯 Goal: Build a C++ class called BankAccount that uses encapsulation to protect the account balance. You will create private data, public methods to interact with it, and show how to use the class safely.

📋 What You'll Learn

Create a class BankAccount with a private variable balance of type double.

Add a public constructor that sets the initial balance.

Add a public method deposit that adds money to balance.

Add a public method withdraw that subtracts money from balance only if there is enough money.

Add a public method getBalance that returns the current balance.

Create an object of BankAccount and demonstrate deposits, withdrawals, and balance checks.

💡 Why This Matters

🌍 Real World

Encapsulation is used in real banking software to protect account data and ensure only valid operations change balances.

💼 Career

Understanding encapsulation is essential for software developers to write secure and maintainable code, especially in finance and data-sensitive applications.

1

Create the BankAccount class with private balance

Create a class called BankAccount with a private variable balance of type double. Do not add any methods yet.

C++

class BankAccount {
private:
    double balance;
    // Your code here
};

Need a hint?

Use the private: keyword to hide the balance variable inside the class.

2

Add constructor to set initial balance

Add a public constructor to BankAccount that takes a double parameter called initialBalance and sets the private balance variable to this value.

C++

class BankAccount {
private:
    double balance;
public:
    BankAccount(double initialBalance) {
        // Your code here
    }
};

Need a hint?

Use the constructor to set the private balance when creating an object.

3

Add deposit and withdraw methods

Add two public methods to BankAccount: deposit that takes a double amount and adds it to balance, and withdraw that takes a double amount and subtracts it from balance only if balance is enough.

C++

class BankAccount {
private:
    double balance;
public:
    BankAccount(double initialBalance) {
        balance = initialBalance;
    }
    void deposit(double amount) {
        // Your code here
    }
    bool withdraw(double amount) {
        // Your code here
    }
};

Need a hint?

Use if to check if there is enough balance before withdrawing.

4

Add getBalance method and test the class

Add a public method getBalance that returns the current balance. Then create a BankAccount object called myAccount with initial balance 100.0. Deposit 50.0, withdraw 30.0, and print the final balance using getBalance.

C++

class BankAccount {
private:
    double balance;
public:
    BankAccount(double initialBalance) {
        balance = initialBalance;
    }
    void deposit(double amount) {
        balance += amount;
    }
    bool withdraw(double amount) {
        if (balance >= amount) {
            balance -= amount;
            return true;
        } else {
            return false;
        }
    }
    double getBalance() {
        // Your code here
    }
};

int main() {
    BankAccount myAccount(100.0);
    myAccount.deposit(50.0);
    myAccount.withdraw(30.0);
    // Your code here
    return 0;
}

Need a hint?

Return the balance in getBalance. Use std::cout to print the balance in main.