Partial Class

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 WindowsFormsApplication1

{

    public partial class partialclass : Form

    {

        public partialclass()

        {

            InitializeComponent();

        }

        partial class bank

        {

            private int mbalance = 3000;

            public int balance

            {

                get { return mbalance;}

                set {mbalance =value;}

            }

        }

        partial class bank

        {

            public void deposit(int amount)

            {

                balance = balance + amount;

            }

            public void withdraw(int amount)

            {

                balance = balance - amount;

            }

        }

        bank b = new bank();

        private void showbal()

        {

            label1.Text = b.balance.ToString();

            textBox1.Text = "";

            textBox1.Focus();

        }

        private void partialclass_Load(object sender, EventArgs e)

        {

            label1.Text = b.balance.ToString();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            b.deposit(Int32.Parse(textBox1.Text));

            showbal();

        }

        private void button2_Click(object sender, EventArgs e)

        {

            b.withdraw(Int32.Parse(textBox1.Text));

            showbal();

        }

    }

}