Constructors and initialization in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a constructor in C#?

A constructor is a special method in a class that runs automatically when an object is created. It sets up the object with initial values.

beginner

How do you define a constructor in a C# class?

You define a constructor by creating a method with the same name as the class and no return type. For example: <pre>public class Car { public Car() { } }</pre>

beginner

What is the purpose of constructor parameters?

Constructor parameters let you pass values when creating an object, so you can set different initial states for each object.

intermediate

What happens if you don't define a constructor in a C# class?

C# provides a default parameterless constructor automatically, which initializes fields to default values like 0 or null.

intermediate

Explain constructor chaining in C#.

Constructor chaining means calling one constructor from another in the same class using the <code>: this(...)</code> syntax to reuse initialization code.

What is the name of a constructor in C#?

A Init

B Same as the class name

C Main

D Constructor

In C#, the constructor must have the same name as the class.

What does a parameterless constructor do?

A Requires parameters to create an object

B Cannot be used in C#

C Initializes object with default values

D Deletes the object

A parameterless constructor sets fields to default values like 0 or null.

How do you call one constructor from another in the same class?

A Using new keyword

B Using base keyword

C Using super()

D Using : this(...) syntax

Constructor chaining uses : this(...) to call another constructor in the same class.

What happens if you define a constructor with parameters but no parameterless constructor?

A No default constructor is created automatically

B Parameterless constructor is still created

C Class cannot be instantiated

D Compiler error always occurs

If you define any constructor, C# does not create a default parameterless constructor automatically.

Which of these is NOT true about constructors?

A Constructors can be called like normal methods

B Constructors can be overloaded

C Constructors have no return type

D Constructors initialize new objects

Constructors cannot be called like normal methods; they run automatically when creating an object.

Describe what a constructor is and why it is useful in C#.

Think about how you prepare a new object when you make it.

Explain constructor chaining and give an example of when you might use it.

Imagine you want to avoid repeating code in multiple constructors.