PILAS

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace pilas_push_pop

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        Pila pil = new Pila(10);

        public void Mostrar()

        {

            dataGridView1.Rows.Clear();

            if (pil.estaVacia())

                return;

            int r = pil.Max - 1;

            for (int i = 0; i <= pil.Tope; i++)

            {

                dataGridView1.RowCount = pil.Max;

                //dataGridView1[0, r].Value = i;

                dataGridView1[0, r].Value = pil[i];

                r--;

            }

        }

        private void button1_Click(object sender, EventArgs e)

        {

            int dato;

            if (sender == button1)

            {

                try

                {

                    dato = Convert.ToInt32(numericUpDown1.Value);

                }

                catch

                {

                    MessageBox.Show("Teclee un dato entero por favor...");

                    return;

                }

                if (pil.llena==true)

                {

                    MessageBox.Show("Pila llena  ** overflow** ");

                    return;

                }

                if (pil.Push(dato))

                {

                    if (dato >= 0)

                    {   

                        Mostrar();

                    }

                }

                else

                    MessageBox.Show("No se pudo poner el dato");

            }

            else if (sender == button2)

            {

                if (pil.vacia==true)

                {

                    MessageBox.Show("La pila esta vacía,  **Underflow** ");

                    return;

                }

                pil.Pop();

                Mostrar();

            }

        }           

    }  

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

    class Pila

    {

        //ATRIBUTOS

        //ARREGLO QUE GUARDA ENTEROS

        private int[] vec = null;

       

        //SE DECLARA UNA VARIABLE TOPE

        private int tope;

        public bool vacia, llena;

        //CONSTRUCTORES

        public Pila()

        {

            vec = new int[5];

            tope = -1;

        }

        public Pila(int n)

        {

            if (n < 1)

                n = 5;

            vec = new int[n];

            tope = -1;

        }

        //Indexador

        public int this[int index]

        {

            get { return vec[index]; }

        }

        //PROPIEDADES

        public int Max

        {

            get { return vec.Length; }

        }

        public int Tope

        {

            get { return tope; }

        }

       

        public bool estaVacia()

        {

            return tope == -1;

        }

        public bool estaLlena()

        {

            return tope == vec.Length - 1;

        }

        public bool Push(int valor)

        {

            vacia = false;

            if (tope == Max)

                llena = true;

           tope++;

            vec[tope] = valor;

           return true;         

        }

        public int  Pop()

        {

            if (tope == 0)

                vacia = true;

            llena = false;

            return vec[tope--];

        }

    }