using System;

public class Program

{

    public class Student

    {

        public string FirstName { get; init; }

        public string LastName { get; init; }

    }

    public static void Main()

    {

        var s = new Student()

        {

            FirstName = "Jared",

        };

        s.LastName = "Parsons"; // Error: LastName is not settable

    }

}