c#的设计模式1
在设计模式中有一种模式叫Builder模式,其原理如下:
StringBuilder类型和String的类型的区别:StringBuilder类型的对象是可以修改的,它指向一个Char结构数组。StringBuilder对象可以用作String对象的容器,用来创建String对象。
我们可以将Builder理解成电饭锅,给这个Builder放进去米和水,经过Builder的Build后,我们就可以取出香喷喷的米饭了。
C#中有一个类叫StringBuilder,输入必要的信息后,就可以取出对应的String。其使用方法如下:
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程序执行结果为: aabbbcccc
请使用StringBuilder对以下打印三角型的程序进行改写,写出新程序。
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答:
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三、 先有鸡还是先有蛋?
到底是先有鸡还是先有蛋?看下面的代码:
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Derived继承自Base,可以说没有Base就没有Derived,可Base里面有一个成员是Derived类型。到底是先有鸡还是先有蛋?这个程序可以正常编译执行并打印结果10。
四、 大瓶子套小瓶子还是小瓶子套大瓶子?
另外一个例子:
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上面的代码似乎描述了"a包含b,b包含a"的关系,到底是大瓶子套小瓶子还是小瓶子套大瓶子呢?
五、 .net本质
关于"先有鸡还是先有蛋"的程序,系统运行后,内存结构如下:
由图中可以看出,根本不存在鸡与蛋的问题,而是型与值的问题以及指针引用的问题。
关于"大瓶子套小瓶子还是小瓶子套大瓶子"问题,系统运行后,内存结构如下:
由于是指针引用,所以也无所谓大瓶子还是小瓶子了。
关于更多内容可以参考《.NET本质论 第1卷:公共语言运行库》。