C#学习8

C#学习8:建一个WPF文件，实现表达式求值，界面比较简陋，添加了一张背景图片，添加背景图片的代码是

<Grid.Background>            <ImageBrush ImageSource="/表达式求值;component/Images/1.jpg" />        </Grid.Background>

再修改background的属性即可

输入的表达式形如：((1+2)*5+1)/4=

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows;using System.Windows.Controls;using System.Windows.Data;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Imaging;using System.Windows.Navigation;using System.Windows.Shapes;namespace 表达式求值{    /// <summary>    /// MainWindow.xaml 的交互逻辑    /// </summary>    public partial class MainWindow : Window    {        int[,] map = new int[7, 7] {  {1,1,-1,-1,-1,1,1},    // 算符间的优先关系                                      {1,1,-1,-1,-1,1,1},                                        {1,1,1,1,-1,1,1},                                        {1,1,1,1,-1,1,1},                                        {-1,-1,-1,-1,-1,0,100},                                        {1,1,1,1,100,1,1},                                        {-1,-1,-1,-1,-1,100,0}                                     };        char[]str=new char[1005];        char[]optr = new char[1005];        double[]opnd = new double[1005];        int t1, t2, k, len;        char ch, zz;        int temp1, temp2;        double a, b;          public MainWindow()        {            InitializeComponent();        }        public int cam(char c)        {            switch (c)            {                case '+': return 0;                case '-': return 1;                case '*': return 2;                case '/': return 3;                case '(': return 4;                case ')': return 5;                case '#': return 6;                default: return -1;            }        }        public double sol(double x, char c, double y)        {            switch (c)            {                case '+': return x + y;                case '-': return x - y;                case '*': return x * y;                case '/': return x / y;                default: return -1;            }        }        public int z(char c)        {            if ('0' <= c && c <= '9' || c == '.')                return 1;            if (c == ' ')                return -1;            return 0;        }          private void button2_Click(object sender, RoutedEventArgs e)        {            this.Close();        }        private void button1_Click(object sender, RoutedEventArgs e)        {            string s = resource.Text;            str = s.ToCharArray();            len = s.Length;            str[len - 1] = '#'; //处理等于号              t1 = t2 = k = 0;            optr[t1++] = '#';            ch = str[k++];            while (ch != '#' || optr[t1 - 1] != '#')            {                if (z(ch) == 1)  //操作数入栈                  {                    double num1,num2,sm;                    int t,flagg;                    num1=num2=0;                    t=k-1;                    flagg=0;                    sm=0.1;                    while (z(str[t]) == 1)                    {                        if (str[t] == '.')                        {                            flagg = 1;                            t++;                            continue;                        }                        if (flagg == 0)                            num1 = num1 * 10 + (str[t] - '0');                        else                        {                            num2 += sm * (str[t] - '0');                            sm *= 0.1;                        }                        t++;                    }                    opnd[t2++] =num1+num2; //把字符串转换成浮点数                    k = t;                    ch = str[k++];                }                else if (z(ch) == -1)                    ch = str[k++];                else                {                    temp1 = cam(optr[t1 - 1]);                    temp2 = cam(ch);                    if (map[temp1,temp2] == -1)  //栈顶元素优先权低                      {                        optr[t1++] = ch;                        ch = str[k++];                    }                    else if (map[temp1,temp2] == 0) //脱括号并接受下一个字符                      {                        t1--;                        ch = str[k++];                    }                    else    //退栈并将运算结果                      {                        zz = optr[--t1];                        a = opnd[--t2];                        b = opnd[--t2];                        opnd[t2++] = sol(b, zz, a);                    }                }              }            result.Text = opnd[0].ToString();        }    }}