Calculator.cs
1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5
6 namespace stratage
7 {
8 public abstract class Calculator //抽象类 Calculator
9 {
10 public abstract double Cal(double a, double b); //抽象方法Cal
11 }
12 public class Add : Calculator //派生类Add继承抽象类Calculator
13 {
14 public override double Cal(double a, double b)//并重写了抽象方法Cal
15 {
16 double result = 0;
17 result = a + b;
18 return result;
19 }
20 }
21 public class Sub : Calculator
22 {
23 public override double Cal(double a, double b)
24 {
25 double result = 0;
26 result = a - b;
27 return result;
28 }
29 }
30 public class Mul : Calculator
31 {
32 public override double Cal(double a, double b)
33 {
34 double result = 0;
35 result = a * b;
36 return result;
37 }
38 }
39 public class Div : Calculator
40 {
41 public override double Cal(double a, double b)
42 {
43 double result = 0;
44 result = a / b;
45 return result;
46 }
47 }
48 public class Context //上下文
49 {
50 private Calculator calculate = null;//实例化一个基类的引用对象
51 public Context(Calculator _cal)//_cal为派生类的一个对象
52 {
53 this.calculate = _cal; //把派生类的对象赋给基类的引用对象
54 }
55 public double Cal(double a, double b, String symbol)
56 {
57 return this.calculate.Cal(a, b);//返回计算结果
58 }
59 }
60 }
Form1.cs
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Windows.Forms;
9 using System.IO;
10
11 namespace stratage
12 {
13 public partial class Form1 : Form
14 {
15 public Form1()
16 {
17 InitializeComponent();
18 }
19 int Count=0;
20 int Right=0;
21 public static String AddSymbol = "+"; //加法
22 public static String SubSymbol = "-"; //减法
23 public static String MulSymbol = "*"; //乘法
24 public static String DivSymbol = "/"; //除法
25 private void textBox4_KeyDown(object sender, KeyEventArgs e)
26 {
27 double a = double.Parse(textBox1.Text); //用来存第一个数
28 string symbol = textBox2.Text; //用来存运算符
29 double b = double.Parse(textBox3.Text); //用来存第二个数
30 Context contex = null; //上下文
31 if (symbol.Equals(AddSymbol)) //若为加号
32 {
33 contex = new Context(new Add()); //加法策略
34 }
35 else if (symbol.Equals(SubSymbol)) //如果减号
36 {
37 contex = new Context(new Sub()); //减法策略
38 }
39 else if (symbol.Equals(MulSymbol)) //若为乘号
40 {
41 contex = new Context(new Mul()); //乘法策略
42 }
43 else if (symbol.Equals(DivSymbol)) //若为除号
44 {
45 contex = new Context(new Div()); //除法策略
46 }
47 string answer = contex.Cal(a, b, symbol).ToString(); //用answer来存计算出来的答案,此时已经计算出a,b两个数的运算结果。
48 if (e.KeyCode == Keys.Enter) //回车操作
49 {
50 string result = textBox1.Text + textBox2.Text + textBox3.Text;//把运算式子存在result里面
51 Count++; //出题总数加一
52 if (textBox4.Text == answer) //如果输入答案与计算出的answer相等
53 {
54 MessageBox.Show("回答正确！"); //弹出回答正确
55 listBox1.Items.Add(result + "=" + textBox4.Text.Trim() + "√");//并把运算式子存在listbox里
56 Right++; //答对题数加一
57 }
58
59 else //如果答错
60 {
61 MessageBox.Show("答题错误！"); //弹出答题错误
62 listBox1.Items.Add(result + "=" + textBox4.Text.Trim() +"×");//同样把运算式子放在listbox
63 }
64 label3.Text = "正确率：" + Convert.ToString(Right * 1.0 / Count * 100).PadRight(5, ' ').Substring(0, 5) + "%";//统计正确率
65 textBox1.Clear();//把文本框清空，进行下一次出题
66 textBox3.Clear();
67 textBox4.Clear();
68 }
69 }
70 private void button1_Click(object sender, EventArgs e)//保存按钮，把已答题目放在txt文件里
71 {
72 sfd.Filter = "(*.txt)|*.txt";
73 if (sfd.ShowDialog() == DialogResult.OK)
74 {
75 string sPath = sfd.FileName;
76 FileStream fs = new FileStream(sPath, FileMode.Create);
77 StreamWriter sw = new StreamWriter(fs, Encoding.UTF8);
78 int iCount = listBox1.Items.Count - 1;
79 for (int i = 0; i <= iCount; i++)
80 {
81 sw.WriteLine(listBox1.Items[i].ToString());
82 }
83 sw.Flush();
84 sw.Close();
85 fs.Close();
86 }
87 }
88 }
89 }
测试截图：
