You can use a variable whose type is a base class to reference instances of a derived class. However, using the variable whose type is the base class, you can use it to access only members of the base class and not members of the derived class. In th…

(转载)http://hi.baidu.com/lylegend13/item/a79f17eb51f5dff7e0a5d43b 1. select count(distinct CName) from Course 2. select count(CName) from (select distinct CName from Course) as temp as可有可无.temp作为别名,若无则提示错误:1248 - Every derived table must have its own…

#include <iostream> struct CloneableBase { ; }; template<class Derived> struct Cloneable : CloneableBase { virtual CloneableBase* clone() const { return new Derived(static_cast<const Derived&>(*this)); } }; struct D1 : Cloneable<D…

原文 关于C#你应该知道的2000件事 下面列出了迄今为止你应该了解的关于C#博客的2000件事的所有帖子. 帖子总数= 1,219 大会 #11 -检查IL使用程序Ildasm.exe d #179 - 什么是大会? #180 - CLR按需加载程序集 #485 - 项目参考和附属组件 #486 - 忽略不必要的项目引用 #705 - 应用程序和类库 #706 - 应用程序域启用应用程序隔离 基本 #1 - Main()签名的样子 #2 - 最小的C#程序 #3 - 谁设计了C#? #4 -…

A derived class inherits all of the members of a base class except for its constructors. You must define a constructor in a derived class unless the base class has defined a default (parameterless) constructor.  If you don’t define a constructor in t…

原文: https://code.google.com/p/googlemock/wiki/CookBook Creating Mock Classes Mocking Private or Protected Methods Mocking Overloaded Methods Mocking Class Templates Mocking Nonvirtual Methods Mocking Free Functions The Nice, the Strict, and the Naggy…

转载自:http://www.weixueyuan.net/view/6329.html 在C++语言中新增了四个关键字static_cast.const_cast.reinterpret_cast和dynamic_cast.这四个关键字都是用于强制类型转换的.我们逐一来介绍这四个关键字. 1) static_cast 在C++语言中static_cast用于数据类型的强制转换,强制将一种数据类型转换为另一种数据类型.例如将整型数据转换为浮点型数据. [例1]C语言所采用的类型转换方式: ; ;…

转自:http://www.cnblogs.com/sujz/articles/2044365.html 派生类的继承方式总结: 继承方式 说明 public 基类的public和protected的成员被派生类继承后,保持原来的状态 private 基类的public和protected的成员被派生类继承后,变成派生类的private成员 protected 基类的public和protected的成员被派生类继承后,变成派生类的protected成员 注:无论何种继承方式,基类的privat…

There is a base class at the root of the hierarchy, from which the other class inherit, directly or indirectly. These inheriting classes are known as derived calsses. The key ideas in Object-Oriented Programming are data abstraction, inheritance and…

When you use the new modifier to hide a base class method, it will still be called by objects whose type is the base class. Objects whose type is the derived class will call the new method in the derived class. Dog kirby = ); // Calls Dog.Bark kirby.…