struct_readonly_method.cs

using System;

namespace CoinChangeProblem.UI
{
    public static class Program
    {
        public static void Main()
        {
            var user = new User("initial_name");
            user.SetName("test_1");
            user.SetName("test_2");
            user.SetName("test_3");
            user.SetName("test_4");
            user.SetName("test_5");
            Console.WriteLine(user.Name);
        }
    }

    public struct User
    {
        public string Name { get; set; }

        public User(string name)
        {
            Name = name;
        }

        public readonly void SetName(string name)
        {
            ChangeName(name);
        }

        private void ChangeName(string newName)
        {
            Name = newName;
        }
    }
}