Why encapsulation is required in C++ - See It in Action

Why Encapsulation is Required in C++

📖 Scenario: Imagine you are building a simple bank account system. You want to keep the account balance safe so that no one can change it directly by mistake. This is where encapsulation helps.

🎯 Goal: You will create a class called BankAccount that keeps the balance private. You will add methods to deposit money, withdraw money, and check the balance safely.

📋 What You'll Learn

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

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

Demonstrate that balance cannot be accessed directly from outside the class

💡 Why This Matters

🌍 Real World

Banks and many software systems use encapsulation to protect sensitive data like account balances or personal information.

💼 Career

Understanding encapsulation is essential for writing safe and maintainable code in professional software development.

1

Create the BankAccount class with private balance

Create a class called BankAccount with a private variable balance of type double initialized to 0.0.

C++

class BankAccount {
private:
    double balance = 0.0;
};

// Your code here

Need a hint?

Use private: to keep balance hidden from outside the class.

2

Add public methods to deposit and withdraw money

Add public methods deposit and withdraw to the BankAccount class. deposit should add a double amount to balance. withdraw should subtract amount from balance only if balance is enough.

C++

class BankAccount {
private:
    double balance = 0.0;
public:
    void deposit(double amount) {
        // Your code here
    }
    void withdraw(double amount) {
        // Your code here
    }
};

Need a hint?

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

3

Add a method to get the current balance

Add a public method getBalance to the BankAccount class that returns the current balance as a double.

C++

class BankAccount {
private:
    double balance = 0.0;
public:
    void deposit(double amount) {
        balance += amount;
    }
    void withdraw(double amount) {
        if (balance >= amount) {
            balance -= amount;
        }
    }
    double getBalance() {
        // Your code here
    }
};

Need a hint?

Return the private balance so outside code can see it safely.

4

Use the BankAccount class and show encapsulation

Create a BankAccount object called myAccount. Deposit 100.0, withdraw 30.0, then print the balance using getBalance(). Try to access balance directly (this should cause an error).

C++

int main() {
    BankAccount myAccount;
    // Your code here
    return 0;
}

Need a hint?

Use myAccount.deposit(100.0); and myAccount.withdraw(30.0); then print myAccount.getBalance().