Constructors - General Questions

What is the output of the following program?

var p = new Pt();
Console.WriteLine(p.X + p.Y);
class Pt
{
    public int X = 3, Y;
    public Pt() { Y = 4; }
}

Constructor chaining within the same class is done with:

What is a private constructor commonly used for?

What is a primary constructor (C# 12)?

An object initialiser such as new P { X = 1 } runs: