Get and set accessors in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Get and set accessors

Start

↓

Create object

↓

Access property

↓

Get accessor runs

↓

Set accessor runs

↓

End

This flow shows how a property is accessed: reading calls the get accessor to return a value, writing calls the set accessor to update the value.

Execution Sample

C Sharp (C#)

class Person {
  private string name;
  public string Name {
    get { return name; }
    set { name = value; }
  }
}

var p = new Person();
p.Name = "Anna";
Console.WriteLine(p.Name);

This code creates a Person object, sets the Name property to "Anna" using the set accessor, then reads it using the get accessor and prints it.

Execution Table

Step	Action	Accessor Called	Variable 'name' Value	Output
1	Create Person object	None	null
2	Set p.Name = "Anna"	set	Anna
3	Get p.Name	get	Anna	Anna printed

💡 Program ends after printing the Name property value.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3
name	null	null	Anna	Anna

Key Moments - 2 Insights

Why does setting p.Name call the set accessor and not the get accessor?

Because in the execution_table at Step 2, the action is setting the property, so the set accessor runs to update the private variable.

What happens if you try to get p.Name before setting it?

The get accessor returns the current value of 'name', which is null initially, as shown in Step 1 where 'name' is null.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'name' after Step 2?

A null

B "" (empty string)

C "Anna"

D undefined

💡 Hint

Check the 'Variable 'name' Value' column at Step 2 in the execution_table.

At which step is the get accessor called?

A Step 3

B Step 2

C Step 1

D Never

💡 Hint

Look at the 'Accessor Called' column in the execution_table.

If you remove the set accessor, what happens when you try to assign p.Name = "Anna"?

A It works normally.

B Compilation error because property is read-only.

C The get accessor runs instead.

D The private variable 'name' updates automatically.

💡 Hint

Properties without set accessors are read-only; assignment causes error.

Concept Snapshot

Get and set accessors define how a property reads and writes data.
Get accessor returns the value.
Set accessor updates the value using 'value' keyword.
Accessing property calls get or set automatically.
Useful to control access to private data.

Full Transcript

This example shows a class Person with a private variable 'name' and a public property Name with get and set accessors. When we create a Person object, 'name' starts as null. Setting p.Name to "Anna" calls the set accessor, which updates 'name' to "Anna". Getting p.Name calls the get accessor, which returns "Anna". The execution table tracks these steps and variable changes. Beginners often wonder why set runs on assignment and get on reading; this is shown clearly in the steps. Also, if the set accessor is missing, assigning to the property causes a compile error because the property is read-only.

Practice

1. What is the main purpose of get and set accessors in a C# class?

easy

A. To handle exceptions automatically

B. To define methods that perform calculations

C. To create variables inside a class

D. To control how a property value is read and changed

Solution

1. Step 1: Understand the role of accessors

   Get and set accessors are used to read and write property values in a controlled way.

2. Step 2: Differentiate from other class members

   They are not methods or variables themselves but control access to data.

3. Final Answer:

   To control how a property value is read and changed -> Option D

4. Quick Check:

   Get/set control property access = A [OK]

Hint: Get/set control property reading and writing [OK]

Common Mistakes:

• Confusing accessors with methods
• Thinking they create variables
• Assuming they handle exceptions automatically

2. Which of the following is the correct syntax for an auto-implemented property with get and set accessors in C#?

easy

A. public int Age { get() set(); }

B. public int Age() { get; set; }

C. public int Age { get; set; }

D. public int Age get; set;

Solution

1. Step 1: Identify correct property syntax

   Auto-properties use curly braces with get and set accessors separated by semicolons.

2. Step 2: Check each option

   public int Age { get; set; } matches the correct syntax: public int Age { get; set; }

3. Final Answer:

   public int Age { get; set; } -> Option C

4. Quick Check:

   Auto-property syntax = C [OK]

Hint: Auto-properties use braces with get; set; inside [OK]

Common Mistakes:

• Using parentheses instead of braces
• Missing semicolons after get and set
• Writing get and set without braces

3. What will be the output of the following C# code?

class Person {
  private string name;
  public string Name {
    get { return name; }
    set { name = value.ToUpper(); }
  }
}

var p = new Person();
p.Name = "alice";
Console.WriteLine(p.Name);

medium

A. alice

B. ALICE

C. Name

D. null

Solution

1. Step 1: Analyze the set accessor behavior

   The set accessor converts the assigned value to uppercase before storing it in the private field.

2. Step 2: Analyze the get accessor output

   The get accessor returns the stored uppercase string.

3. Final Answer:

   ALICE -> Option B

4. Quick Check:

   Set converts to uppercase, output = ALICE [OK]

Hint: Set modifies value before storing, get returns stored value [OK]

Common Mistakes:

• Ignoring the ToUpper() call in set
• Assuming original case is preserved
• Confusing field and property names

4. Identify the error in this property definition:

public int Score {
  get { return score; }
  set score = value; }
}

medium

A. Incorrect set accessor syntax

B. Missing semicolon after return statement

C. Missing private field declaration

D. Property name should be lowercase

Solution

1. Step 1: Check set accessor syntax

   The set accessor must use braces { } around its code block, but here it is missing the opening brace.

2. Step 2: Confirm other parts

   The return statement has a semicolon, private field may be declared elsewhere, and property names are PascalCase by convention.

3. Final Answer:

   Incorrect set accessor syntax -> Option A

4. Quick Check:

   Set accessor needs braces = A [OK]

Hint: Set accessor must have braces around code block [OK]

Common Mistakes:

• Omitting braces in set accessor
• Confusing property and field names
• Assuming property names must be lowercase

5. You want to create a property Age that only allows values between 0 and 120. Which implementation correctly enforces this using get and set accessors?

hard

A. private int age; public int Age { get { return age; } set { if (value >= 0 && value <= 120) age = value; } }

B. public int Age { get; set; } // No validation needed

C. private int age; public int Age { get { return age; } set { age = value; } }

D. private int age; public int Age { get { return age; } set { if (value > 0) age = value; } }

Solution

1. Step 1: Check validation logic in set accessor

   private int age; public int Age { get { return age; } set { if (value >= 0 && value <= 120) age = value; } } checks if value is between 0 and 120 before assigning it to the private field.

2. Step 2: Compare other options

   The auto-implemented property has no validation. The simple backing field assignment lacks checks. The partial validation only checks if value > 0, missing the upper limit.

3. Final Answer:

   private int age; public int Age { get { return age; } set { if (value >= 0 && value <= 120) age = value; } } -> Option A

4. Quick Check:

   Set accessor validates range 0-120 = B [OK]

Hint: Use if condition in set to validate value range [OK]

Common Mistakes:

• Not validating upper limit
• Assigning value without checks
• Assuming auto-properties validate automatically