Access modifiers (public, private, internal) in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Access modifiers (public, private, internal)

Start

↓

Define class members

↓

Apply access modifiers

↓

public: accessible anywhere

↓

private: accessible only inside class

↓

internal: accessible inside same assembly

↓

Use members

↓

Access allowed?

Yes/No↓

End

This flow shows how class members are defined with access modifiers and how access is checked based on modifier rules.

Execution Sample

C Sharp (C#)

class MyClass {
  public int a = 1;
  private int b = 2;
  internal int c = 3;
}

MyClass obj = new MyClass();
Console.WriteLine(obj.a);

Defines a class with public, private, and internal members and accesses the public member from outside.

Execution Table

Step	Action	Member Accessed	Access Modifier	Access Allowed	Output/Result
1	Create object obj	N/A	N/A	N/A	obj created
2	Access obj.a	a	public	Yes	Prints 1
3	Access obj.b	b	private	No	Compile error: 'b' is inaccessible
4	Access obj.c	c	internal	Yes if same assembly, else No	Prints 3 or error
5	End	N/A	N/A	N/A	Execution stops

💡 Execution stops after access attempts; private member access fails outside class.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
obj	null	MyClass instance	MyClass instance	MyClass instance	MyClass instance
obj.a	N/A	1	1	1	1
obj.b	N/A	2 (private)	2 (private)	2 (private)	2 (private)
obj.c	N/A	3 (internal)	3 (internal)	3 (internal)	3 (internal)

Key Moments - 3 Insights

Why can't we access the private member 'b' from outside the class?

Because 'b' is marked private, it is only accessible inside the class. The execution_table row 3 shows the compile error when trying to access it outside.

When can we access the internal member 'c'?

The internal member 'c' can be accessed anywhere inside the same assembly (project). If accessed from outside the assembly, access is denied as shown in execution_table row 4.

What does the public modifier allow?

Public members like 'a' can be accessed from anywhere, inside or outside the class and assembly, as shown in execution_table row 2.

Visual Quiz - 3 Questions

Look at the execution_table, what happens when we try to access obj.b?

A Compile error because 'b' is private

B Access is allowed and value 2 is printed

C Access is allowed only inside the same assembly

D Value 3 is printed

💡 Hint

Check execution_table row 3 where accessing obj.b causes a compile error.

At which step does the program print the value of the public member?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at execution_table row 2 where obj.a is accessed and prints 1.

If the internal member 'c' is accessed from a different assembly, what will happen?

A Access allowed and prints 3

B Compile error due to internal access restriction

C Compile error due to private access

D Access allowed only if public

💡 Hint

Refer to execution_table row 4 explaining internal access depends on assembly.

Concept Snapshot

Access modifiers control who can use class members:
- public: accessible anywhere
- private: accessible only inside the class
- internal: accessible inside the same assembly
Use modifiers to protect or expose data safely.

Full Transcript

This visual execution shows how access modifiers in C# control access to class members. Public members can be accessed anywhere, private members only inside the class, and internal members only inside the same assembly. The example creates an object and tries to access members with different modifiers. Access to private members from outside causes a compile error. Internal members are accessible only if accessed within the same assembly. This helps protect data and control visibility in programs.