大話設計模式--計算器

時間 2019-12-05

標籤大話設計模式計算器简体版

原文原文鏈接

做爲一名程序員，必要的總結是不能夠缺乏的。計劃從如今開始到明年年末將《大話設計模式》這本書中所列舉的設計模式都紀錄一遍用於之後工做的提高！javascript

簡單工廠之計算器css

寫這個功能以前，我須要整理一下寫代碼的基本思路：寫程序必需要以能複用，易於維護爲原則，必定要使用面向對象的三大特徵封裝繼承和多態。引用《大話設計模式》中的一個例子在活字印刷出來以前，印刷的模板都是一次性使用的，所以一本書的成本過高，這樣大規模使用是很難實現的。若是放到當今這個以流量爲王的時代絕對會被淘汰。代碼java

public class Operation程序員
```
{
```
```
private double _numbA = 0;
```
```
private double _numbB = 0;
```
```
public double _NumbA
```
```
{
```
```
get
```
```
{
```
```
return _numbA;
```
```
}
```
```
set
```
```
{
```
```
_numbA = value;
```
```
}
```
```
}
```
```
public double _NumbB
```
```
{
```
```
get
```
```
{
```
```
return _numbB;
```
```
}
```
```
set
```
```
{
```
```
_numbB = value;
```
```
}
```
```
}
```
```
public virtual double getResult()
```
```
{
```
```
double result = 0;
```
```
return result;
```
```
}
```
```
}
```

//上邊是抽象出來其餘運算類須要繼承的父類。web

//下邊寫具體實現
//加法類ajax

public class OperationAdd : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA + _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//減法類算法

public class OperationSub : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA - _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//乘法類express

public class OperationMulti : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA * _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//除法類設計模式

public class OperationDivde : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
if (_NumbB == 0)
```
```
{
```

throw new Exception("除數不能爲零！！");

```
}
```
```
result = _NumbA / _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//後臺類已經寫好了，前臺控制檯程序也好，webform程序也好均可以使用。我是以asp.net webform配合ajax來實現的。 //前臺數據經過ajax傳遞到後臺通常處理性程序(ashx)文件，數據處理後將數據傳遞到前臺。 //在這裏須要添加一個ashx類的父類，經過反射的方式簡化調用程序。asp.net

//Parent.ashx中代碼

public class Parent : IHttpHandler
```
{
```
```
private string m_flag;
```
```
public string Flag
```
```
{
```
```
get { return m_flag; }
```
```
set { m_flag = value; }
```
```
}
```

public void ProcessRequest(HttpContext context)

```
{
```
```
if (context.Request["flag"] != null)
```

m_flag = context.Request["flag"].ToString();

var methodName = context.Request["flag"];

```
Type objType = this.GetType();
```

MethodInfo method = objType.GetMethod(methodName == null ? "" : methodName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);

```
if (method != null)
```
```
{
```

HttpContext[] objParams = new HttpContext[] { context };

```
method.Invoke(this, objParams);
```
```
}
```
```
else
```
```
{
```
```
Other(context);
```
```
}
```
```
}
```

public virtual void Other(HttpContext context)

```
{
```
```
}
```
```
public bool IsReusable
```
```
{
```
```
get
```
```
{
```
```
return false;
```
```
}
```
```
}
```
```
}
```

//建立調用類，調用類中的代碼

public class Caculate : Parent
```
{
```

public void NumOperate(HttpContext context)

```
{
```

var expression = context.Request["expression"];//這裏是將用戶的表達式獲取過來

var operateFlag = context.Request["operateFlag"].ToCharArray();

var ExpreArry = expression.Split(operateFlag);//而後經過用戶輸入的運算符來分割

```
Operation operate = null;
```
```
switch (operateFlag[0])
```
```
{
```
```
case '+':
```
```
operate = new OperationAdd();
```
```
break;
```
```
case '-':
```
```
operate = new OperationSub();
```
```
break;
```
```
case '*':
```
```
operate = new OperationMulti();
```
```
break;
```
```
case '/':
```
```
operate = new OperationDivde();
```
```
break;
```
```
}
```

operate._NumbA = Convert.ToDouble(ExpreArry[0]);//不管是加減乘除均可以使用同一種方式來調用

operate._NumbB = Convert.ToDouble(ExpreArry[1]);

```
var result = operate.getResult();
```
```
context.Response.Write(result);
```
```
context.Response.End();
```
```
}
```
```
}
```

//後臺調用完畢，下邊開始寫前臺調用方式。首先須要引用jQuery文件，而後就可使用jQuery中的方法了。在這裏不展現引用(太簡單)

//前臺HTML佈局使用的是table佈局

<body>
```
<table id="caclator">
```
```
<tr>
```
```
<td colspan="5">
```

<input type="text" id="txtExpression" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="MC" id="btnMC" />

```
</td>
```
```
<td>
```

<input type="button" value="MR" id="btnMR" />

```
</td>
```
```
<td>
```

<input type="button" value="MS" id="btnMS" />

```
</td>
```
```
<td>
```

<input type="button" value="M+" id="btnMAdd" />

```
</td>
```
```
<td>
```

<input type="button" value="M-" id="btnMSub" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="←" id="btnBackSpace" />

```
</td>
```
```
<td>
```

<input type="button" value="CE" id="btnCE" />

```
</td>
```
```
<td>
```

<input type="button" value="C" id="btnC" />

```
</td>
```
```
<td>
```

<input type="button" value="±" id="Button4" />

```
</td>
```
```
<td>
```

<input type="button" value="√" id="Button5" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="7" id="btnNumSeven" />

```
</td>
```
```
<td>
```

<input type="button" value="8" id="btnNumEight" />

```
</td>
```
```
<td>
```

<input type="button" value="9" id="btnNumNine" />

```
</td>
```
```
<td>
```

<input type="button" value="/" id="btnOperDivide" />

```
</td>
```
```
<td>
```

<input type="button" value="%" id="Button10" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="4" id="btnNumFour" />

```
</td>
```
```
<td>
```

<input type="button" value="5" id="btnNumFive" />

```
</td>
```
```
<td>
```

<input type="button" value="6" id="btnNumSix" />

```
</td>
```
```
<td>
```

<input type="button" value="*" id="btnOperMulti" />

```
</td>
```
```
<td>
```

<input type="button" value="1/x" id="Button12" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="1" id="btnNumOne" />

```
</td>
```
```
<td>
```

<input type="button" value="2" id="btnNumTwo" />

```
</td>
```
```
<td>
```

<input type="button" value="3" id="btnNumThree" />

```
</td>
```
```
<td>
```

<input type="button" value="-" id="btnOperSub" />

```
</td>
```
```
<td rowspan="2">
```

<input type="button" value="=" id="btnEques" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td colspan="2">
```

<input type="button" value="0" id="btnNumZero" />

```
</td>
```
```
<td>
```

<input type="button" value="." id="btnPoint" />

```
</td>
```
```
<td>
```

<input type="button" value="+" id="btnOperAdd" />

```
</td>
```
```
</tr>
```
```
</table>
```
</body>

//僅僅實現了+-*/最基本的算法，所以沒有涉及到的按鈕id名稱就沒修改
//如下是css樣式設置

<style type="text/css">
```
input[type='button']
```
```
{
```
```
height: 25px;
```
```
width: 35px;
```
```
}
```
```
input[type='button'][value='0']
```
```
{
```
```
height: 25px;
```
```
width: 72px;
```
```
}
```
```
input[type='button'][value='=']
```
```
{
```
```
height: 52px;
```
```
width: 35px;
```
```
}
```
```
input[type='text']
```
```
{
```
```
width: 185px;
```
```
}
```
```
</style>
```

//運行圖仿照win7中計算器樣式

//最後添加jQuery代碼

<script type="text/javascript">

var expression = ""; //存放用戶表達式

var operateFlag = ""; //存放用戶操做 +-*/

```
$(function () {
```
```
$("#txtExpression").val('');
```

$("#caclator").offset({ top: 300, left: 900 });

```
$.each($("input"), function (i, j) {
```
```
if (j.id.indexOf("Num") > -1) {
```
```
$("#" + j.id).click(function () {
```
```
expression += this.value;
```
```
$("#txtExpression").val(expression);
```
```
})
```
```
}
```
```
})
```
```
$.each($("input"), function (i, j) {
```
```
if (j.id.indexOf("Oper") > -1) {
```
```
$("#" + j.id).click(function () {
```
```
expression += this.value;
```
```
$("#txtExpression").val(expression);
```
```
if (this.value != ".") {
```
```
operateFlag = "";
```
```
operateFlag = this.value;
```
```
}
```
```
})
```
```
}
```
```
})
```
```
$("#btnEques").click(function () {
```

var url = "/Handler/Caculate.ashx?t=" + new Date();

```
$.ajax({
```
```
type: "POST",
```
```
url: url,
```

data: { flag: "NumOperate", expression: expression, operateFlag: operateFlag },

```
async: false,
```
```
cache: false,
```
```
success: function (msg) {
```
```
expression = "";
```
```
$("#txtExpression").val(msg);
```
```
},
```
```
error: function (msg) {
```
```
if (msg.status == 500) {
```

alert("錯誤，不容許的操做！");//若是除數爲0，那麼就會彈出提示信息

```
}
```
```
}
```
```
})
```
```
})
```
```
})
```
</script>

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