c#中四则运算计算器涉及的代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace 计算器
{
public partial class Form1 : Form
{
string t,u;
int x;
double z;
public Form1()
{
InitializeComponent();
}

private void button15_Click(object sender, EventArgs e)
{
int j;
for (int i = 0; i < 1000000; i++)
{
Math.DivRem(i, 1000, out j);
if (j == 0)
progressBar1.PerformStep();
}

double g = Convert.ToDouble(u);
double h = Convert.ToDouble(t);
if (x == 1)
{
z = g / h;
}
else if (x == 2)
{
z = g + h;
}
else if (x == 3)
{
z = g - h;
}
else if (x == 0)
{
z = g * h;
}
string m = Convert.ToString(z);

label1.Text = m;

}

private void button1_Click(object sender, EventArgs e)
{

t += "1";
label1.Text = t;
}

private void button2_Click(object sender, EventArgs e)
{

t += "2";
label1.Text = t;
}

private void button3_Click(object sender, EventArgs e)
{
t += "3";
label1.Text = t;
}

private void button4_Click(object sender, EventArgs e)
{
t += "4";
label1.Text = t;
}

private void button5_Click(object sender, EventArgs e)
{
t += "5";
label1.Text = t;
}

private void button6_Click(object sender, EventArgs e)
{
t += "6";
label1.Text = t;
}

private void button7_Click(object sender, EventArgs e)
{
t += "7";
label1.Text = t;
}

private void button8_Click(object sender, EventArgs e)
{
t += "8";
label1.Text = t;
}

private void button9_Click(object sender, EventArgs e)
{
t += "9";
label1.Text = t;
}

private void button13_Click(object sender, EventArgs e)
{
u = t;
t = "";
x = 0;
label1.Text = t;
}

private void button10_Click(object sender, EventArgs e)
{
t += "0";
label1.Text = t;
}

private void button14_Click(object sender, EventArgs e)
{
u = t;
t = "";
x = 1;
label1.Text = t;
}

private void button11_Click(object sender, EventArgs e)
{
u = t;
t = "";
x = 2;
label1.Text = t;
}

private void button12_Click(object sender, EventArgs e)
{
u = t;
t = "";
x = 3;
label1.Text = t;
}

private void button16_Click(object sender, EventArgs e)
{
t = "";
label1.Text = "";
}

private void button17_Click_1(object sender, EventArgs e)
{
t += ".";
label1.Text = t;
}

private void timer1_Tick(object sender, EventArgs e)
{
label3.Text = DateTime.Now.ToString();
}
}
}
//button11是+ 12是- 13是* 14是/