using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Converter
{
    class Converter
    {
        private double usd;
        private double eur;
        private double rub;
        private double uah;

        private double usd_coeff = 25.81;
        private double eur_coeff = 28.87;
        private double rub_coeff = 0.40;

        public double Usd
        {
            set
            {
                if(value >= 0) { usd = value; }
            }
            get { return usd; }
        }

        public double Eur
        {
            set
            {
                if (value >= 0) { eur = value; }
            }
            get { return eur; }
        }

        public double Rub
        {
            set
            {
                if (value >= 0) { rub = value; }
            }
            get { return rub; }
        }

        public double Uah
        {
            set
            {
                if (value >= 0) { uah = value; }
            }
            get { return uah; }
        }

        public Converter()
        {
            usd = 0;
            eur = 0;
            rub = 0;
        }

        public Converter(double usd, double eur, double rub)
        {
            usd = usd_coeff * uah;
            eur = eur_coeff * uah;
            rub = rub_coeff * uah;
        }

        public void Switch(int s)
        {
            switch (s)
            {
                case 1:
                    Console.WriteLine("Вы выбрали  USD");
                    break;
                case 2:
                    Console.WriteLine("Вы выбрали EUR");
                    break;
                case 3:
                    Console.WriteLine("Вы выбрали RUB");
                    break;
                default:
                    Console.WriteLine("Вы выбрали  USD");
                    break;
            }
        }
    }

    class Program
    {
        static void Main()
        {
            Converter convert = new Converter();
            Console.ReadKey();
        }
    }
}