自己动手写计算器V1.0

今天突发奇想，想着看了还几个设计模式了，倒不如写点东西来实践它们。发现计算器这种就比较合适，打算随着设计模式的学习，会对计算器不断的做改进。

包括功能的增加和算法的改进。初学者难免犯错，希望大家不吝指教。

　　　　计算器V1.0：主要实现了计算器最常见的加减乘除功能，同时还有一个特殊功能，例如：我们执行完1+2后，如果点击等号，会执行加法运算输出结果。但我们如果点击的是运算符（如-），那么不仅会执行加法运算，还会将-号放置到执行结果后，表示这次执行的将会是减法运算。

　　　　代码:Operator类负责使用简单工厂模式来生成加减乘除运算。

Form窗体后台代码：

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 计算器{    public partial class Form1 : Form    {        //简述：变量集中声明处        StringBuilder num1 = new StringBuilder();        StringBuilder num2 = new StringBuilder();        public void CheckTextbox(string num)        {            StringBuilder str = new StringBuilder();            if (this.textBox1.Text != "")            {                str.Append(this.textBox1.Text);                str.Append(num);                this.textBox1.Text = str.ToString();            }            else            {                this.textBox1.Text = num;            }        }        //简述：输入运算符。 2016-5-13 张杨        public void CheckYunSuan(string myOperator)        {            StringBuilder str = new StringBuilder();            if (this.textBox1.Text != "")            {                if (textBox1.Text.Contains("+") || textBox1.Text.Contains("-") || textBox1.Text.Contains("*") || textBox1.Text.Contains("/"))                {                    ShowResult();                }                str.Append(this.textBox1.Text);                str.Append(myOperator);                this.textBox1.Text = str.ToString();            }            else            {                this.textBox1.Text = myOperator;            }        }        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            CheckTextbox("1");        }        private void button2_Click(object sender, EventArgs e)        {            CheckTextbox("2");        }        private void button3_Click(object sender, EventArgs e)        {            CheckTextbox("3");        }        private void button4_Click(object sender, EventArgs e)        {            CheckTextbox("4");        }        private void button5_Click(object sender, EventArgs e)        {            CheckTextbox("5");        }        private void button6_Click(object sender, EventArgs e)        {            CheckTextbox("6");        }        private void button7_Click(object sender, EventArgs e)        {            CheckTextbox("7");        }        private void button8_Click(object sender, EventArgs e)        {            CheckTextbox("8");        }        private void button9_Click(object sender, EventArgs e)        {            CheckTextbox("9");        }        //简述：下面的为加减乘除功能。        //2016-5-13 张杨        private void button10_Click(object sender, EventArgs e)        {            CheckYunSuan("+");        }        private void button11_Click(object sender, EventArgs e)        {            CheckYunSuan("-");        }        private void button12_Click(object sender, EventArgs e)        {            CheckYunSuan("*");        }        private void button13_Click(object sender, EventArgs e)        {            CheckYunSuan("/");        }        private void button14_Click(object sender, EventArgs e)        {            this.textBox1.Text = String.Empty;        }        //简述：判断字符是否为运算符。 2016-5-13  张杨        public bool isOperator(char key)        {            if (key == '+' || key == '-' || key == '*' || key == '/')            {                return true;            }            else            {                return false;            }        }        //简述：计算结果。  2016-5-13    张杨        private void ShowResult()        {            string strText = this.textBox1.Text;            char myOperator = 'A';            int flag = 0;            string result = "";            foreach (char key in strText)            {                if (isOperator(key))                {                    flag = 1;                    myOperator = key;                    continue;                }                else                {                    switch (flag)                    {                        case 0: num1.Append(key); break;                        case 1: num2.Append(key); break;                    }                }            }            result = OperatorFactory.GetResult(myOperator, double.Parse(num1.ToString()), double.Parse(num2.ToString()));            num1 = num1.Remove(0, num1.Length);            num2 = num2.Remove(0, num2.Length);            this.textBox1.Text = result;        }        private void button15_Click(object sender, EventArgs e)        {            ShowResult();        }    }}

 

重点来了，Operator类：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace 计算器{    //简述：加减乘除处理类，采用了简单工厂模式。 2016-5-13 张杨    class Operator    {        public virtual string GetResult(double num1, double num2)        {            return "error";        }    }    public class OperatorFactory    {       static Operator myOperator=new Operator();        public static string GetResult(char key,double num1,double num2)        {            switch (key)            {                case '+': myOperator = new plusOperator(); break;                case '-': myOperator = new jianOperator(); break;                case '*': myOperator = new chenOperator(); break;                case '/': myOperator = new chuOperator(); break;            }            return myOperator.GetResult(num1,num2);        }    }    class plusOperator : Operator    {        public  override string GetResult(double num1, double num2)        {            return (num1 + num2).ToString();        }    }    class jianOperator : Operator    {        public override string GetResult(double num1, double num2)        {            return (num1 - num2).ToString();        }    }    class chenOperator : Operator    {        public override string GetResult(double num1, double num2)        {            return (num1 * num2).ToString();        }    }    class chuOperator : Operator    {        public override string GetResult(double num1, double num2)        {            if (num2 == 0)            {                return "除数不能为0";            }            else            {                return (num1 / num2).ToString();            }        }    }}

运行结果：