Get and set accessors in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this C# code using get and set accessors?

Consider the following C# class with a property using get and set accessors. What will be printed when the program runs?

C Sharp (C#)

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

class Program {
    static void Main() {
        Person p = new Person();
        p.Name = "alice";
        System.Console.WriteLine(p.Name);
    }
}

A null

B alice

C Alice

D ALICE

💡 Hint

Look at how the set accessor modifies the value before storing it.

The set accessor converts the input string to uppercase before storing it in the private field. So when we get the Name property, it returns the uppercase version.

❓ Predict Output

intermediate

What value does the property return after setting it?

Given this C# code, what will be the output?

C Sharp (C#)

class Counter {
    private int count;
    public int Count {
        get { return count; }
        set {
            if (value >= 0) count = value;
        }
    }
}

class Program {
    static void Main() {
        Counter c = new Counter();
        c.Count = -5;
        System.Console.WriteLine(c.Count);
    }
}

A -5

B 0

C Throws an exception

D Uninitialized value

💡 Hint

Check what happens when the set accessor receives a negative value.

The set accessor only assigns the value if it is zero or positive. Since -5 is negative, the private field remains at its default value 0.

🔧 Debug

advanced

Why does this property cause a stack overflow error?

Examine the following C# property. Why does it cause a runtime error?

C Sharp (C#)

class Sample {
    private int number;
    public int Number {
        get { return Number; }
        set { Number = value; }
    }
}

A The get and set accessors recursively call themselves causing a stack overflow.

B The private field 'number' is not initialized causing a null reference exception.

C The property is missing a semicolon causing a syntax error.

D The property uses an invalid data type causing a compile error.

💡 Hint

Look at what the get and set accessors are returning and assigning.

The get accessor returns the property itself, not the private field, so it calls itself infinitely. The set accessor also assigns to the property, causing infinite recursion. This leads to a stack overflow error.

📝 Syntax

advanced

Which option correctly defines a read-only property with a private set accessor?

Choose the correct C# property syntax that allows reading the value publicly but only setting it privately within the class.

A public int Age { get private; set; }

B public int Age { private get; set; }

C public int Age { get; private set; }

D public int Age { get; set; private }

💡 Hint

Remember the correct order and syntax for access modifiers on accessors.

Option C correctly places 'private' before 'set;' to restrict setting access. Other options have invalid syntax or misplaced modifiers.

🚀 Application

expert

How many items are in the dictionary after this code runs?

Analyze this C# code using a property with get and set accessors that modify a dictionary. How many key-value pairs does the dictionary contain after execution?

C Sharp (C#)

class DataStore {
    public Dictionary<string, int> data = new();
    public int this[string key] {
        get => data.ContainsKey(key) ? data[key] : -1;
        set {
            if (value >= 0) data[key] = value;
            else if (data.ContainsKey(key)) data.Remove(key);
        }
    }
}

class Program {
    static void Main() {
        DataStore store = new DataStore();
        store["a"] = 10;
        store["b"] = 20;
        store["a"] = -5;
        store["c"] = 0;
        store["b"] = -1;
        System.Console.WriteLine(store.data.Count);
    }
}

A 1

B 2

C 3

D 0

💡 Hint

Track how the set accessor adds, updates, or removes keys based on the value.

Initially, keys 'a' and 'b' are added. Setting 'a' to -5 removes it. 'c' is added with 0. Setting 'b' to -1 removes it. Only 'c' remains, so count is 1.

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