Constructors: default, parameterised, static, private, chaining

2. Constructors: default, parameterised, static, private, chaining

Basic★ Must knowLesson 2 of 15

csharp

public class Logger
{
    public static readonly DateTime LoadedAt;
    static Logger() { LoadedAt = DateTime.UtcNow; }      // static ctor: once per type, before first use

    public string Name { get; }
    public Logger() : this("default") { }                // chaining to another ctor
    public Logger(string name) { Name = name; }
}

public class Settings
{
    private Settings() { }                               // private ctor: no outside 'new'
    public static Settings Load() => new Settings();     // factory method / Singleton
}

public class Admin : User
{
    public Admin(string email) : base(email) { }         // call base constructor
}

If you write no constructor, C# provides a parameterless one. Writing any constructor removes it.
Order: static fields → static ctor (once) → instance field initialisers → base ctor → derived ctor body.
Copy constructor: a constructor taking another instance of the same type (records generate one).