Constructors

In C# classes, a constructor is a special method inside a class that runs automatically when you create an object with new. It sets up the object with initial values, so you don't have to assign them one by one.

A constructor has the same name as the class and no return type.

Constructors - A

Let's add a default constructor to our Person class. A "default" constructor is one that takes no parameters. This will set up default values for each Person object we create.

class Person {
    public string Name;
    public int Age;
    public double Height;

    // Default constructor
    public Person() {
        Name = "NO NAME";
        Age = 0;
        Height = 0.0;
    }
}

With this default constructor, every time we create a new Person without giving it any values, it starts with these safe defaults instead of empty or zero values we never chose on purpose.

Let's see an example:

Person p = new Person(); // Calls the default constructor
Console.WriteLine($"{p.Name} - {p.Age} - {p.Height}");

OUTPUT:

NO NAME - 0 - 0

Constructors - B

We can also create a constructor that takes parameters to set the name, age, and height when we create a Person. Here we'll use this. so it's clear which Name we mean the class's field or the parameter.