C#练习：实现基本计算器功能，考虑运算符优先级

设计思路：

1 用StringBuilder类变量StrData，动态保存用户输入的数据及运算符
2 以加减运算符为分割符，对字符串进行分割，得到字符串数组StrDataArr[]
3 遍历字符串数组StrDataArr，查找其中含有乘除运算的项，对该项进行计算
4 经过乘除计算之后，数组StrDataArr存储的实际结果为加减运算符的操作数，再进行加减运算

主要方法：
StringBuilder类：动态存储数据
string.Split()方法：根据运算符优先级多次分割处理数据
string.Contains()方法：判断是否包含特定字符

Double.Parse()方法：将字符串形式的数字转换为数字(可简单理解为去掉双引号)

代码实现：

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 Frm_Main : Form    {        StringBuilder StrData = new StringBuilder(); //数据及运算符保存        public Frm_Main()        {            InitializeComponent();        }        private void Frm_Main_Load(object sender, EventArgs e)        {            calcResult.Clear();            calcProcess.Clear();        }        public void DataProcess(string data)        {            calcProcess.Text = calcProcess.Text + data;            StrData.Append(data);        }         //0        private void button16_Click(object sender, EventArgs e)        {            DataProcess("0");        }        //1        private void button12_Click(object sender, EventArgs e)        {            DataProcess("1");        }                //2        private void button11_Click(object sender, EventArgs e)        {            DataProcess("2");        }        //3        private void button10_Click(object sender, EventArgs e)        {            DataProcess("3");        }        //4        private void button5_Click(object sender, EventArgs e)        {            DataProcess("4");        }        //5        private void button6_Click(object sender, EventArgs e)        {            DataProcess("5");        }        //6        private void button7_Click(object sender, EventArgs e)        {            DataProcess("6");        }        //7        private void button1_Click(object sender, EventArgs e)        {            DataProcess("7");        }        //8        private void button2_Click(object sender, EventArgs e)        {            DataProcess("8");        }        //9        private void button3_Click(object sender, EventArgs e)        {            DataProcess("9");        }        //小数点        private void button15_Click(object sender, EventArgs e)        {            DataProcess(".");        }        //除        private void button4_Click(object sender, EventArgs e)        {            DataProcess("÷");        }        //乘        private void button8_Click(object sender, EventArgs e)        {            DataProcess("×");        }        //减        private void button9_Click(object sender, EventArgs e)        {            DataProcess("－");        }        //加        private void button13_Click(object sender, EventArgs e)        {            DataProcess("＋");        }        //回退        private void button18_Click(object sender, EventArgs e)        {            StrData.Remove(StrData.Length-1,1);            calcProcess.Text = StrData.ToString();        }        //clear        private void button20_Click(object sender, EventArgs e)        {            calcResult.Clear();            calcProcess.Clear();            StrData.Clear();        }        double CalcData(string s)        {            char[] splitor = { '×', '÷' };            string[] strArr = s.Split(splitor);            double tempData=0;             int i = 0;            tempData = Double.Parse(strArr[0]);             foreach(char temps in s)            {                switch (temps)                {                    case '÷':                        tempData = tempData / Double.Parse(strArr[i+1]);                        i++;                        break;                    case '×':                        tempData = tempData * Double.Parse(strArr[i + 1]);                        i++;                        break;                    default:                        break;                }            }            return tempData;        }        //等于        private void button14_Click(object sender, EventArgs e)        {            char[] SplitSymbol = { '＋', '－' };            string StrDataTemp = StrData.ToString(); ;            string[] StrDataArr= StrDataTemp.Split(SplitSymbol);            double ResultData = 0;            int j = 0;            //先以加减运算符为分隔符分割字符串，处理分割后数组中的乘除运算            for (int i=0; i< StrDataArr.Length;i++)            {                if(StrDataArr[i].Contains("×")|| StrDataArr[i].Contains("÷"))                {                    StrDataArr[i] = CalcData(StrDataArr[i]).ToString();                }            }            //加减运算            ResultData= Double.Parse(StrDataArr[0]);            foreach (char temps in StrDataTemp)            {                switch (temps)                {                    case '－':                        ResultData = ResultData - Double.Parse(StrDataArr[j + 1]);                        j++;                        break;                    case '＋':                        ResultData = ResultData + Double.Parse(StrDataArr[j + 1]);                        j++;                        break;                    default:                        break;                }            }            calcResult.Text = ResultData.ToString();        }        private void calcResult_TextChanged(object sender, EventArgs e)        {        }        private void calcProcess_TextChanged(object sender, EventArgs e)        {        }           }}