Constructors

Learn how constructors initialize objects, including default, parameterized, and overloaded constructors.

What is a Constructor?

A constructor is a special method that runs automatically when an object is created with `new`. It shares the class's name and has no return type, and is typically used to set up initial values.

Parameterized Constructors

class Student
{
    public string Name;
    public int Age;

    public Student(string name, int age)
    {
        Name = name;
        Age = age;
    }
}

var student = new Student("Aarav", 20);
Console.WriteLine($"{student.Name} is {student.Age}");

Output

Click Run to see what this code prints.

Constructor Overloading

Like methods, constructors can be overloaded to support creating objects in different ways.

class Student
{
    public string Name;
    public int Age;

    public Student(string name, int age)
    {
        Name = name;
        Age = age;
    }

    public Student(string name) : this(name, 18) // calls the other constructor
    {
    }
}

The this Keyword

`this` refers to the current object instance. It's especially useful for disambiguating a field from a constructor parameter with the same name.

class Point
{
    public int X;
    public int Y;

    public Point(int x, int y)
    {
        this.X = x; // this.X is the field, x is the parameter
        this.Y = y;
    }
}

FAQs

What if I don't write a constructor at all?

C# provides a free, parameterless default constructor automatically — but only if you don't define any constructor of your own.

Summary

Constructors initialize an object when it's created.
They can be overloaded to support different creation patterns.
`this` refers to the current instance, useful for resolving naming conflicts.

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