C#做一个简单的计算器，有按钮、界面，想不通怎么实现3+9-2这样的三个数以上做运算。

[8988CVB]

苦逼学生党一支 这是期末作业唉 想完善一下这简单的计算器实现3+5+1
Form1.cs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 Calculator
{
    public partial class Form1 : Form
    {
        double a = 0, b = 0, adds = 0;
        bool c = false;
        bool cjj = true;
        string d;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form_Load(object sender, EventArgs e)
        {
        }
        private void button9_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "7";
        }
        private void button10_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "8";
        }
        private void button11_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "9";
        }
        private void button5_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "4";
        }
        private void button6_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "5";
        }
        private void button7_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "6";
        }
        private void button1_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "1";
        }
        private void button2_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "2";
        }
        private void button3_click(object sender, EventArgs e)
        {
            if (c)
            {
                textBox1.Text = "";
                c = false;
            }
            textBox1.Text += "3";
        }
        private void button14_click(object sender, EventArgs e)
        {
            if (c)
            {
                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);
            }
        }
        //要实现三个以上数相加必须在按下第二个+符号按钮之前，把前两个数相加，
        //2+3=5+3=8
        private void button4_click(object sender, EventArgs e)
        {
                c = true;
                b = double.Parse(textBox1.Text);
                d = "+";
        }
        private void button8_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)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "/";
        }
        private void button13_click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "*2";
        }
        private void button15_click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "sqrt";
        }
        private void button18_click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "log";
        }
        private void button19_click(object sender, EventArgs e)
        {
            c = true;
            b = double.Parse(textBox1.Text);
            d = "ln";
        }
        //这个函数是按等于之后才工作的
        private void button20_click(object sender, EventArgs e)
        {
            switch (d)
            {
                case "+":
                    a = b + double.Parse(textBox1.Text);//将文本框内容转换成double类型   
                    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 "*2":
                    a = b * double.Parse(textBox1.Text);
                    break;
                case "sqrt":
                    a = Math.Sqrt(b);
                    break;
                case "log":
                    a = Math.Log(double.Parse(textBox1.Text), b);
                    break;
                case "ln":
                    a = Math.Log(b, Math.E);
                    break;
            }
            textBox1.Text = a + "";
            c = false;
        }
        private void button17_click(object sender, EventArgs e)
        {
            textBox1.Text = "";
        }
    }
}

由于字数有限Form1.Designer.cs代码就不上了 它也就是在每个按钮代码下面调用对应的函数

[X-i-n]

new DataTable().Computer() Int.Parse(String) 或者用js

[GStrangeclown]

给你个笨方法，等待用户输入后每一步输入符号都计算一下，注意第一个符号没有计算要做下处理 或者等待用户输入完成，吧输入的所有先乘除后加减的算完，也就相当于两个数字做的处理了，街区符号什么的可以自己思考一下

[老马吃草]

写的太麻烦了，需要的话我可以帮你写个简单的

[放开我的胡萝卜]

你把前两个数加减后保存到内存在个第三个加减就行了，这样你处理的时候其实一直是对两个数加减

[nikolaichow]

使用字符串自动计算功能

//通过字符串自动计算结果
    public class Expression
    {
        object instance;
        MethodInfo method;
        /// <summary>
        /// 表达试运算
        /// </summary>
        /// <param name="expression">表达试</param>
        public Expression(string expression)
        {
            if (expression.IndexOf("return") < 0) expression = "return " + expression + ";";
            string className = "Expression";
            string methodName = "Compute";
            CompilerParameters p = new CompilerParameters();
            p.GenerateInMemory = true;
            CompilerResults cr = new CSharpCodeProvider().CompileAssemblyFromSource(p, string.
              Format("using System;sealed class {0}{{public double {1}(double x){{{2}}}}}",
              className, methodName, expression));
            if (cr.Errors.Count > 0)
            {
                string msg = "Expression(\"" + expression + "\"): \n";
                foreach (CompilerError err in cr.Errors) msg += err.ToString() + "\n";
                throw new Exception(msg);
            }
            instance = cr.CompiledAssembly.CreateInstance(className);
            method = instance.GetType().GetMethod(methodName);
        }
        /// <summary>
        /// 处理数据
        /// </summary>
        /// <param name="x"></param>
        /// <returns>返回计算值</returns>
        public double Compute(double x)
        {
            return (double)method.Invoke(instance, new object[] { x });
        }
    }

调用：

string s="1+2+3";
Expression expression = new Expression(s);
double d = expression.Compute(0);

[风吹腚腚凉]

C# 计算器 百度 谷歌 搜狗你爱用什么用什么。 下载一份源码，然后学习一下，我觉得你们学校的书上应该有相似的例子，你这么简单的东西都搞不定？

[小野妹子也编码]

建议你用策略模式编写一个计算器，很有意思。灵活性很强。

[software_artisan]

这个你需要学习『表达式树』才行。

[夏天的枫]

我记得计算器有简单计算器和科学计算器啊，简单计算器就是按下一个运算符号就计算出上一个和当前输入的值的运算，科学的嘛就是在输入“=”过后运算出前面的结果，感觉楼上的方法可以一试。 最后，注意下代码的严谨，特别是double.Parse()这类的。。。万一不是数字咋整？

[zhang_qxian]

http://blog.csdn.net/ghostbear/article/details/7764510