using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace test
{
    /// <summary>
    /// Логика взаимодействия для MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public class A
        {
            public int b = 0;

            public A()
            {
                this.b = 0;
            }

            public A(int b)
            {
                this.b = b;
            }
        }

        private A tmp = new A();
        private List<A> ass = new List<A>();
        private A pos = new A();
        public MainWindow()
        {
            InitializeComponent();
            pos.b = 5;
        }

        public A func(A b, A a)
        {
            return (b.b < 4) ? a : new A(-a.b);
        }

        private void print_ass()
        {
            String text = "";
            foreach (A a in ass)
                text += a.b + " | ";
            L1.Content = text;
        }

        //Лесенка в ass должно лежать  1 2 3 4 -3 -2 -1 0
        private void Button_Click(object sender, RoutedEventArgs e)
        {

            A last = new A(tmp.b);
            tmp = func(last, tmp);
            tmp.b += 1;
            ass.Add(tmp);

            print_ass();
        }

        //Замена последнего значения
        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            tmp = func(pos, tmp);
            print_ass();
        }
    }
}