Data hiding in C++ - Mini Project: Build & Apply

Data Hiding in C++

📖 Scenario: Imagine you are creating a simple bank account system. You want to keep the account balance safe so that it cannot be changed directly from outside the account. This is called data hiding.

🎯 Goal: You will create a class called BankAccount that hides the balance inside it. You will add a way to check the balance safely and a way to add money to the account.

📋 What You'll Learn

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

Add a public method getBalance() that returns the current balance.

Add a public method deposit(double amount) that adds money to the balance.

Use data hiding to prevent direct access to balance from outside the class.

💡 Why This Matters

🌍 Real World

Data hiding is used in real bank systems to protect account balances from accidental or unauthorized changes.

💼 Career

Understanding data hiding is important for writing secure and reliable code in software development jobs.

1

Create the BankAccount class with a 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 the private: keyword to hide the balance variable inside the class.

2

Add a public method to get the balance

Add a public method called getBalance() that returns the value of balance. Use public: to make the method accessible outside the class.

C++

class BankAccount {
private:
    double balance = 0.0;
public:
    double getBalance() {
        // Your code here
    }
};

Need a hint?

The getBalance() method should return the private balance variable.

3

Add a public method to deposit money

Add a public method called deposit that takes a double amount parameter and adds it to balance.

C++

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

Need a hint?

The deposit method should add the amount to the private balance.

4

Create an object and test the methods

Create an object called myAccount of class BankAccount. Use deposit(100.0) to add money and then print the balance using getBalance().

C++

class BankAccount {
private:
    double balance = 0.0;
public:
    double getBalance() {
        return balance;
    }
    void deposit(double amount) {
        balance += amount;
    }
};

int main() {
    // Your code here
}

Need a hint?

Use std::cout to print the balance returned by getBalance().