C#编写一个计算器

编写一个计算器，练习在窗体上添加控件、调整控件的布局，设置或修改控件属性，编写事件处理程序的方法。

代码：

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

namespace Lab07_1
{
    public partial class form1 : Form
    {
        double a = 0;
        double b = 0;
        bool c = false;
        string d; 
        public form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "1"; 
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button5_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "5"; 

        }

        private void button13_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "0";
            if (d == "/")
            {
                textBox1.Clear();
                MessageBox.Show("除数不能为零", "错误提示", MessageBoxButtons.OK,
                MessageBoxIcon.Warning);
            } 

        }

        private void button10_Click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "-"; 

        }

        private void 雨轩计算机_Load(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "2"; 

        }

        private void button7_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "7"; 
        }

        private void button8_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "8"; 

        }

        private void button9_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "9"; 
        }

        private void button4_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "4"; 

        }

        private void button6_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "6"; 

        }

        private void button3_Click(object sender, EventArgs e)
        {
            if (c == true)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "3"; 

        }

        private void button14_Click(object sender, EventArgs e)
        {
            textBox1.Text = ""; 
        }

        private void button15_Click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "+"; 

        }

        private void button11_Click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "*"; 

        }

        private void button12_Click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "/"; 

        }

        private void button16_Click(object sender, EventArgs e)
        {
            switch (d)
            {
                case "+": a = b + double.Parse(textBox1.Text); break;
                case "-": a = b - double.Parse(textBox1.Text); break;
                case "*": a = b * double.Parse(textBox1.Text); break;
                case "/": a = b / double.Parse(textBox1.Text); break;
                case "平方": a = b * b; break;
                case "开方": a =Math.Sqrt(b); break;
                case "log": a = Math.Log10(b); break;
                case "ln": a = Math.Log(b); break;
            }
            textBox1.Text = a + "";
            c = true; 

        }

        private void button20_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "") { MessageBox.Show("请先输入值再计算！", "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Warning); }
            else
            {
                c = true;
                b = double.Parse(textBox1.Text);
                d = "ln";
            }
        }

        private void button17_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "") { MessageBox.Show("请先输入值再计算！", "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Warning); }
            else
            {
                c = true;
                b = double.Parse(textBox1.Text);
                d = "平方";
            }
        }

        private void button18_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "") { MessageBox.Show("请先输入值再计算！", "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Warning); }
            else
            {
                c = true;
                b = double.Parse(textBox1.Text);
                d = "开方";
            }
        }

        private void button19_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "") { MessageBox.Show("请先输入值再计算！", "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Warning); }
            else
            {
                c = true;
                b = double.Parse(textBox1.Text);
                d = "log";
            }
        }
    }
}

界面演示：