Value equality in records in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of comparing two records with same values

What is the output of this C# code snippet?

C Sharp (C#)

public record Person(string Name, int Age);

var p1 = new Person("Alice", 30);
var p2 = new Person("Alice", 30);

Console.WriteLine(p1 == p2);

A True

B False

C Compilation error

D Runtime exception

💡 Hint

Records in C# have built-in value equality.

Records automatically implement value equality, so two records with the same values are equal using == operator.

❓ Predict Output

intermediate

Output of comparing record and class with same properties

What is the output of this C# code snippet?

C Sharp (C#)

public record PersonRecord(string Name, int Age);
public class PersonClass { public string Name { get; init; } public int Age { get; init; } }

var r = new PersonRecord("Bob", 25);
var c = new PersonClass { Name = "Bob", Age = 25 };

Console.WriteLine(r.Equals(c));

A True

B Runtime exception

C Compilation error

D False

💡 Hint

Records and classes have different equality implementations.

Record equality checks type and values; comparing to a class instance returns false.

🔧 Debug

advanced

Why does this record equality fail?

Consider this code snippet. Why does the equality check return false? public record Point(int X, int Y); var p1 = new Point(1, 2); var p2 = new Point(1, 3); Console.WriteLine(p1 == p2);

C Sharp (C#)

public record Point(int X, int Y);

var p1 = new Point(1, 2);
var p2 = new Point(1, 3);

Console.WriteLine(p1 == p2);

A Because the Y values differ, so the records are not equal

B Because records cannot be compared with == operator

C Because the X values differ, so the records are not equal

D Because the record does not override Equals method

💡 Hint

Check the values of both records' properties.

Records compare all properties for equality; since Y differs, the records are not equal.

📝 Syntax

advanced

Which record declaration is invalid?

Which of the following C# record declarations will cause a compilation error?

A public record Car(string Make, string Model);

B public record Car { public string Make { get; init; } public string Model { get; init; } }

C public record Car(string Make, string Model) { public int Year; }

D public record Car(string Make, string Model) { public int Year { get; set; } }

💡 Hint

Check if the record has invalid field declarations.

Records cannot have public fields; they must use properties. Option C declares a public field 'Year', causing a compilation error.

🚀 Application

expert

How many items in the HashSet after adding records?

Given this code, how many items will the HashSet contain after execution?

C Sharp (C#)

public record Employee(string Id, string Name);

var set = new HashSet<Employee>();
set.Add(new Employee("E01", "John"));
set.Add(new Employee("E01", "John"));
set.Add(new Employee("E02", "Jane"));
set.Add(new Employee("E01", "John"));

Console.WriteLine(set.Count);

A 1

B 2

C 3

D 4

💡 Hint

HashSet uses equality to avoid duplicates.

Records have value equality, so duplicates with same values are not added. The set contains two unique employees.