面向对象是软件开发的一种方法，产生的目标是增强应用程序代码的可重用性和可靠性，同时减少应用程序的维护工作。一个对象可以由其它的对象来创建，以此构造更复杂的对象。当这样的对象工作的很好时，设计者就不必再关心对象的内部结构。因此面向对象的软件设计方法效率很高-Object-oriented software development is a method of generating the aim is to enhance the application code reusability and reliability, while reducing application maintenance. An object can be created by another object, thereby construct more complex objects. When such an object work well, the designer will not have to care about the internal structure of the object. Therefore, an object-oriented software design methods is very efficient