Protected access modifier in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Protected access modifier

Define Base Class with protected member

↓

Create Derived Class inheriting Base

↓

Access protected member inside Derived

↓

Use Derived object to call method accessing protected member

↓

Protected member NOT accessible outside inheritance

↓

END

Shows how a protected member is accessible inside derived classes but not outside.

Execution Sample

C Sharp (C#)

class Base {
  protected int number = 42;
}
class Derived : Base {
  public int GetNumber() { return number; }
}

Defines a base class with a protected number and a derived class that accesses it.

Execution Table

Step	Action	Evaluation	Result
1	Create Base object	Base.number is protected	Cannot access number outside Base or Derived
2	Create Derived object	Derived inherits Base.number	Derived.number accessible inside Derived
3	Call Derived.GetNumber()	Returns protected number	Returns 42
4	Try access Derived.number outside class	Access denied	Compilation error
5	End	No further access	Execution stops

💡 Protected member is accessible only within Base and Derived classes, not outside.

Variable Tracker

Variable	Start	After Derived Creation	After GetNumber Call	Final
number	42 (in Base)	42 (inherited by Derived)	42 (returned by GetNumber)	42

Key Moments - 2 Insights

Why can't we access 'number' directly from a Derived object outside the class?

Because 'number' is protected, it is only accessible inside Base and classes derived from Base, not from outside code (see execution_table step 4).

How does Derived class access the protected member 'number'?

Derived inherits 'number' from Base and can access it directly inside its methods (see execution_table step 3).

Visual Quiz - 3 Questions

Look at the execution table, what value does Derived.GetNumber() return at step 3?

A 42

B 0

C Compilation error

D Cannot access

💡 Hint

Check execution_table row with Step 3 showing the returned value.

At which step does the code fail to access the protected member from outside the class?

A Step 2

B Step 4

C Step 3

D Step 1

💡 Hint

Look for the step mentioning 'Compilation error' in execution_table.

If 'number' was public instead of protected, what would change in the execution table?

A Step 3 would fail

B Step 2 would fail

C Step 4 would succeed accessing number

D No change

💡 Hint

Think about accessibility from outside the class in step 4.

Concept Snapshot

protected member:
- Accessible inside class and derived classes only
- Not accessible from outside objects
- Allows controlled inheritance access
- Use to hide details but allow subclass use

Full Transcript

This example shows how the protected access modifier works in C#. A base class defines a protected variable 'number'. A derived class inherits from the base and can access 'number' inside its methods. When we create an object of the derived class and call its method, it returns the protected number. However, trying to access 'number' directly from outside the classes causes a compilation error. This demonstrates that protected members are accessible only within the class and its subclasses, not from outside code.