#11 C# Pila Enlazada Visual

    class N
    {
        public int v;
        public N s;
        public N(int vv, N ss)
        {
            v = vv;
            s = ss;
        }
    }
    class PE
    {
        N u;
        public PE()
        {
            u = null;
        }
        public void metodo1(int vv)
        {
            N nu = new N(vv, u);
            u = nu;
        }
        public int metodo2()
        {
            N naux;
            int val;
            if (u == null)
                return -1;
            naux = u;
            u = naux.s;
            val = naux.v;
            return val;
        }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            dataGridView1.RowCount = 4;
            dataGridView1.Rows.Add();
        }
        PE exam = new PE();
        int tam = 4;
        private void button2_Click(object sender, EventArgs e)
        {
            if(tam>=0&&tam<4)
            {
                textBox2.Text = exam.metodo2().ToString();
                dataGridView1[0, tam].Value = "";
                dataGridView1[0, ++tam].Value = "";
            }
            else
            {
                dataGridView1[0, tam].Value = "no hay datos";
                return;
            }
            if (tam >= 0)
                dataGridView1[0, tam].Value = "Tope";
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int dato;
            dato = Convert.ToInt32(textBox1.Text);
            textBox1.Text = "";
            if(tam!=0)
            {
                exam.metodo1(dato);
                dataGridView1[0, tam].Value = "";
                dataGridView1[0, tam--].Value = dato;
            }
            else
            {
                dataGridView1[0, tam].Value = "Lista llena";
                return;
            }
            if (tam <= 0)
                dataGridView1[0, tam].Value = "Tope";
            textBox1.Select();
        }
   }