[C基础入门课件.ppt

冗余的解决方案 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 继承的符号: 利用继承实现Student类和Teacher类继承自Person类. Student类和Teacher类继承父类的属性和方法. Student类和Teacher类还有自己独有的属性和方法. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 继承的使用 class Student:Person{}; class Teacher:Person{}; 子类继承了父类的成员,子类还可以有自己的成员. Person叫做父类(基类) Student和Teacher叫子类(派生类) Student继承了Person类 Person类派生了Teacher类 在c#中,所有的类都直接或间接的继承自了object类.(当我们定义一个类的时候,如果没有写:继承一个类,那么这个类就继承了object类) Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 练习: 写一个Student类和一个Teacher类,他们都有一个打招呼的方法,不同的是Studetn打招呼是说大家好,我叫XX,我今年XX岁了,我的爱好是XXX,Teacher的打招呼的方法是说大家好,我叫XX,我今年XX岁了,我已经工作XX年了? Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 显示调用父类的构造方法 实例化子类时是否调用了父类的构造方法?顺序如何? 利用构造方法设置公共属性,也就是说若父类的构造方法有参数,应该如何处理呢? 显示调用父类的构造方法,关键字: base Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. protected protected访问修饰符不允许其他非子类访问 修改刚刚的练习,父类中把访问修饰符改成protected子类中还能被调用到吗?其他非子类能调用吗? 继承的传递性. 继承的单根性. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 类型转换(lsp) Person p = new Teacher(); 子类可以隐式的转换成父类. Teacher t=(Teacher)p; is和as typeA is type B 仅判断 typeA as TypeB 先判断,再转换 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 练习: 自己定义一个父类Person,两个子类Teacher和Student类.Person写一个有参数的构造方法. 自己试试,子类可以自动转父类,父类转子类要通过强转.为了不出错,可以先通过is判断或用as转换. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. ArrayList和HashTable 为什么要用ArrayList和HashTable ArrayList元素的增加、插入、删除、清空、排序、反转。 HashTable的增、删、查、判存。 foreach Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. 异常与异常处理 传统