结果是你可以用衍生类的对象替代基类的对象。
As a result, you can exactly substitute an object of the derived class for an object of the base class.
经常在设计过程中，你想要基础类只把接口提供给衍生类。
Often in a design, you want the base class to present only an interface for its derived classes.
在衍生类中，您可以替代虚拟方法，从而改变组件的内部行为。
In derived classes, you can override virtual methods, thus changing the internal behavior of the component.
但是你也会发现有时候你很明显的必须去给衍生类增加新的方法。
But you'll find that there are times when it's equally clear that you must add new functions to the interface of a derived class.
这意味着基类和衍生类拥有相同的类型和行为，这是没有意义的。
That means objects of the derived class have not only the same type, they also have the same behavior, which doesn't seem particularly interesting.
因为基类和衍生类拥有相同的接口，因此这个接口必须要有必要的实现。
Since both the base class and derived class have the same interface, there must be some implementation to go along with that interface.
你对这个家族类能做的最重要的一件事就是把衍生类当作一个基类去对待。
One of the most important things you do with such a family of classes is to treat an object of a derived class as an object of the base class.
这意味着基类不能完成你所要求的全部功能，所以你在衍生类中新增了方法。
This means that the base class simply didn't do as much as you wanted it to, so you add more functions.
该方法目前没有任何效果，但可用于衍生类中，以实施其自定义的更新的项目部署。
The method currently does nothing, but is available for derived classes to implement their own custom update project implementation.
使用基类对象指针或引用的函数必须能够在不了解衍生类的条件下使用衍生类的对象。
Functions that use Pointers or references to base classes must be able to use objects of derived classes without knowing it.
因为我们可以通过能给类发送的消息知道这个类，所以这意味着衍生类和基类属于同种类型。
Since we know the type of a class by the messages we can send to it, this means that the derived class is the same type as the base class.
如果你只是简单的继承一个类而不做其他的事情，那么这个基类的方法便会顺延到衍生类中。
If you simply inherit a class and don't do anything else, the methods from the base-class interface come right along into the derived class.
你有两种方法去区分衍生类和它所继承的原始基类：你可以简单的为衍生类加入标识性的方法。
You have two ways to differentiate your new derived class from the original base class it inherits from. The first is quite straightforward: you simply add brand new functions to the derived class.
如果你使用类向导来生成继承自cview或其衍生类的新类，则动态创建所需的一切都已经为你准备好了。
If you use the class Wizard to derive your classes from any CView or its derivate, the necessary steps for implementing a dynamic creation are done for you.
PHP还提供了get _ called _ class供您大量使用，因为您要实现的设计模式常常会需要衍生类的类名。
PHP also gives you the get_called_class, which you will use heavily because many of the design patterns you'll implement require the class name of derived classes.
糖苷，是糖或糖的衍生物与另一类非糖物质通过糖的端基碳原子链接而成的化合物。
Glycosides are certain molecules in which a sugar part bound to some other part through its anomeric carbon to another group.
这些基金不拥有股票或债券类的资产，但它们能和投行进行衍生交易，投行则担保将目标标准点的收益传到账上。
These funds do not own assets like shares or bonds; instead they arrange a derivative deal with an investment bank, which guarantees to deliver the return of the targeted benchmark.
要使用一个扩展，您应该直接创建一个扩展子类对象，然后使用、添加、或者重写特性到父类(它从其中衍生的)。
To use an extension, you directly create an object of the extension subclass, which can then use, add, or override features to the parent class it is derived from.
虽然贝尔斯登还没有确认持有的是哪一类衍生证券，我们可以从这些基金几个月前致客户的信函中窥得一些特点。
Although Bear Stearns has not yet admitted which versions of these derivatives it held, one can glean some characteristics from letters the funds sent to investors months ago.
有人认为房屋市场的崩溃随时会成为一个类似的推动因素，导致一类衍生品的诞生，以容许投资者对冲住宅地产的价格波动风险。
Some think that the housing meltdown is poised to be a similar catalyst for derivatives that allow investors to hedge against movements in the price of residential property.
这其中也包括了对最佳执行规定的实行的担忧。最佳执行规定是针对象在场外交易的公司债券或者特别设计的衍生工具类证券，而不是股票。
These include worries over the application of best-execution rules to securities other than shares, such as corporate bonds or specialised derivatives, that are traded off-exchange.
GPL类软件有许多不同的衍生分类，也有其他很多授权协议都提供了上述的自由权利，包括beerware和WTFPL。
There are many different variations of GPL software and many other licenses that would still provide the freedoms above, including beerware and WTFPL.
ExtJS的扩展是从类或者子类衍生出来的，为支持现有Ext JS类包含附加特性而设计的。
An extension for ext JS is a derived class or a subclass, which is designed to allow the inclusion of additional features to existing ext JS classes.
本章简单介绍了吡咯类衍生物在医药，农药，生物，高分子以及功能性材料方面的应用。
This chapter simply introduces the application of pyrrole and pyrrole 'derivatives in medicine, pesticide, biology, polymer material and photochromism.
嘌呤衍生物是一类重要的医药中间体。
Purine derivative is an important pharmaceutical intermediate of extensive funtion.
聚苹果酸及其衍生物作为一类新型的生物高分子同样具有一些独特的性质。
As a new type of biopolymers, poly (malic acid) and its derivatives also possess some unique properties.
用显色络合物络合比和试剂结构研究并初步探讨了不对称变色酸双偶氮类衍生物与贵金属元素的络合机理。
The complexing mechanism of unsymmetric bis-arylazo derivative of chromotropic acid and precious metal elements was studied using composition ratio of the color complex and constitution of reagents.
酱文化是指由酱类调味品及其衍生物所生成的文化。
Sauce condiment and its derivate brought into the formation of sauce culture.
本文以股指类衍生金融工具的一种——股票指数期权为研究对象，侧重于用数量方法来阐述其在我国开发应用的意义。
Targeted at one of the stock index derivative instruments-stock index option, this paper does some research work to elaborate the significance of developing it in China.
我们对四环素类抗生素的化学反应和结构修饰进行了一些初步的探索，制备了一些四环素类衍生物。
Some primary research to the chemical modification of tetracyclines were carried out. Several tetracycline derivatives were prepared.
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