Access specifiers in C++ - Mini Project: Build & Apply

Access Specifiers in C++

📖 Scenario: You are creating a simple program to understand how different access specifiers work in C++ classes. Access specifiers control which parts of your program can see and use the data inside a class.

🎯 Goal: Build a C++ class with public, private, and protected members, then write code to access these members and see which are accessible.

📋 What You'll Learn

Create a class named Box with three member variables: length (public), width (private), and height (protected).

Add a public member function setWidth to set the private width.

Add a public member function getWidth to get the private width.

Create an object of Box in main and access the length directly.

Use the public functions to set and get the width.

Try to access height directly from main and observe the error (commented out).

💡 Why This Matters

🌍 Real World

Access specifiers help protect important data inside classes and control how other parts of a program can use that data.

💼 Career

Understanding access specifiers is essential for writing safe and maintainable C++ code in software development jobs.

1

Create the Box class with public, private, and protected members

Create a class called Box with three member variables: length as public, width as private, and height as protected. Set their types to int.

C++

class Box {
    // Your code here
};

Need a hint?

Use public:, private:, and protected: labels inside the class to set access levels.

2

Add public functions to set and get the private width

Inside the Box class, add a public member function setWidth that takes an int parameter and sets the private width. Also add a public member function getWidth that returns the private width.

C++

class Box {
public:
    int length;

    // Add setWidth and getWidth functions here

private:
    int width;
protected:
    int height;
};

Need a hint?

Remember, public functions can access private members inside the class.

3

Create a Box object and set length and width

In the main function, create an object called box of type Box. Set box.length to 10 directly. Use box.setWidth(5) to set the width.

C++

int main() {
    // Create Box object and set length and width
    
    // Your code here
    return 0;
}

Need a hint?

Objects access public members directly and private members via public functions.

4

Print length and width, and try to access height

In main, print box.length and box.getWidth(). Also add a commented line trying to access box.height directly (this should cause an error if uncommented).

C++

int main() {
    Box box;
    box.length = 10;
    box.setWidth(5);
    
    // Print length and width
    
    // Try to access height (commented out)
    
    // Your code here
    return 0;
}

Need a hint?

Use cout to print values. Access height directly will cause an error, so keep it commented.