Why encapsulation matters in C Sharp (C#) - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of accessing private field directly

What will be the output of this C# code when trying to access a private field directly?

C Sharp (C#)

using System;
class BankAccount {
    private decimal balance = 1000m;
}

class Program {
    static void Main() {
        BankAccount account = new BankAccount();
        Console.WriteLine(account.balance);
        Console.WriteLine("Accessing balance directly");
    }
}

A 1000

B 0

C Compilation error: 'BankAccount.balance' is inaccessible due to its protection level

D Runtime error: NullReferenceException

💡 Hint

Private fields cannot be accessed outside their class.

The private field 'balance' is not accessible outside the BankAccount class, so trying to access it directly causes a compilation error.

❓ Predict Output

intermediate

Output of using public property to access private field

What will be the output of this C# code that uses a public property to access a private field?

C Sharp (C#)

using System;
class BankAccount {
    private decimal balance = 1000m;
    public decimal Balance {
        get { return balance; }
    }
}

class Program {
    static void Main() {
        BankAccount account = new BankAccount();
        Console.WriteLine(account.Balance);
    }
}

A Compilation error: Cannot access private field

B 1000

C 0

D Runtime error: NullReferenceException

💡 Hint

Public properties can expose private fields safely.

The public property Balance allows read-only access to the private field balance, so the output is 1000.

🧠 Conceptual

advanced

Why encapsulation improves code safety

Which of the following best explains why encapsulation improves code safety in object-oriented programming?

A It hides internal data and only exposes controlled access, preventing unintended changes.

B It forces the program to run faster by removing all checks on data.

C It makes all data public so any part of the program can modify it freely.

D It allows direct access to all variables to simplify debugging.

💡 Hint

Think about how hiding details helps protect data.

Encapsulation hides internal details and exposes only what is necessary, which prevents accidental or harmful changes to data.

🔧 Debug

advanced

Identify the encapsulation violation

Which option shows a violation of encapsulation principles in C#?

C Sharp (C#)

class Person {
    public string name;
    private int age;
}

A Making 'name' public allows external code to change it directly.

B Making 'age' private hides it from external access.

C Using a private field for 'age' protects it from unintended changes.

D Using properties to access 'age' is a violation of encapsulation.

💡 Hint

Encapsulation means hiding data from outside code.

Making 'name' public breaks encapsulation because external code can change it without control.

🚀 Application

expert

Result of modifying private field via method

What will be the output of this C# program that modifies a private field using a public method?

C Sharp (C#)

using System;
class Counter {
    private int count = 0;
    public void Increment() {
        count++;
    }
    public int GetCount() {
        return count;
    }
}

class Program {
    static void Main() {
        Counter c = new Counter();
        c.Increment();
        c.Increment();
        Console.WriteLine(c.GetCount());
    }
}

A 0

B Runtime error: NullReferenceException

C Compilation error: Cannot access private field

D 2

💡 Hint

Methods can safely modify private data inside the class.

The Increment method increases the private count field twice, so GetCount returns 2.