using System;
using System.Diagnostics;
using System.Collections.Generic;


public class Tarjeta {
	public /*required*/ int Num {
		get => this._num;
		init {
			Debug.Assert( value > 0, "num. de tarjeta debe ser positivo" );
			this._num = value;
			this.calculaCVC();
		}
	}
	
	public /*required*/ DateOnly Caduca {
		get => this._caduca;
		init {
			Debug.Assert( value > DateOnly.FromDateTime( DateTime.Now ), "caducidad debe ser a futuro" );
			this._caduca = value;
		}
	}
	
	public int CVC { get; private set; }
	
	public Tarjeta(int num, DateOnly caduca)
	{
		Debug.Assert( num > 0, "num. de tarjeta debe ser positivo" );
		Debug.Assert( caduca > DateOnly.FromDateTime( DateTime.Now ), "caducidad debe ser a futuro" );
	
		this.Num = num;
		this.Caduca = caduca;
		this.calculaCVC();
	}
	
	private void calculaCVC()
	{
		this.CVC = this.Num % 1000;
	}
	
	public override string ToString()
	{
		return $"{this.Num} ({this.Caduca}, {this.CVC})";
	}
	
	private int _num;
	private DateOnly _caduca;
}


public class Test
{
	public static void Main()
	{
	/*
		var t1 = new Tarjeta {
			Num = 548901687,
			Caduca = new DateOnly( 2034, 11, 5 )
		};
	*/	
		var t2 = new Tarjeta( 548901687, new DateOnly( 2034, 11, 5 ) );
		
		// Console.WriteLine( t1 );
		Console.WriteLine( t2 );
	}
}