1.关于重载运算符
2.包含与委托（不太明白）
class Program
{
class Radio
{
protected bool on_off;
public void On()
{
if (!on_off )Console .WriteLine ("Radio is now on!");
on_off = true;
}
public void Off()
{
if (!on_off) Console.WriteLine("Radio is now off!");
on_off = false;
}
}
}
class AlarmClock
{
private int currentTime;
private int alarmTime;
protected virtual void SoundAlarm()
{
Console.WriteLine("Buzz!");
}
public void Run()
{
for (int currentTime = 0; currentTime < 43200; currentTime++)
{
SetCurrentTime(currentTime);
if (GetCurrentTime() == GetAlarmTime())
{
Console.WriteLine("Current Time = {0}!", currentTime);
SoundAlarm();
break;
}
}
}
public int GetCurrentTime()
{
return currentTime;
}
public void SetCurrentTime(int aTime)
{
currentTime = aTime;
}
public int GetAlarmTime()
{
return alarmTime;
}
public void SetAlarmTime(int aTime)
{
alarmTime = aTime;
}
}
class ClockRadio : AlarmClock
{
private Radio radio;//声明其他成员的变量
public bool radioAlarm;
public ClockRadio()
{
radio = new Radio();
radioAlarm = false;
}
//-------------Delegate to Radio---------------
public void RadioOn()
{
radio.On();
}
public void RadioOff()
{
radio.Off();
}
//--------------Overridde AlarmClock-----------------
protected override void SoundAlarm()
{
if (radioAlarm)
{
RadioOn();
}
else
{
base.SoundAlarm();
}
}
//-------New ClockRadio functionalitiy------------
public void SetRadioAlarm(bool useRadio)
{
radioAlarm = useRadio;
}
}
class ContInh
{
static int Main(string[] args)
{
ClockRadio clockRadio;
clockRadio = new ClockRadio();
clockRadio.SetRadioAlarm(true);
clockRadio.SetAlarmTime(100);
clockRadio.Run();
//wait for user to acknowledge the results
Console.WriteLine("Hit Enter to terminate....");
Console.Read();
return 0;
}
}
错误提示：
错误 1 未能找到类型或命名空间名称“Radio”(是否缺少 using 指令或程序集引用?) c:\users\administrator\documents\visual studio 2012\Projects\ConsoleApplication36\ConsoleApplication36\Program.cs 75 17 ConsoleApplication36
is 关键字与as关键字
//类 类对象 方法 接口
public interface IPrintMessage
{
void Print();
}
class Class1
{
public void Print()
{
Console.WriteLine("from class1 ");
}
}
class Class2 : IPrintMessage
{
public void Print()
{
Console.WriteLine("from class2");
}
}
class Mainclass
{
public static void Main()
{
PrintClass PrintObject = new PrintClass ();
PrintObject.PrintMessage();
}
}
class PrintClass
{
public void PrintMessage()
{
Class1 Object1 = new Class1();
Class2 Object2 = new Class2();
PrintMessageFromObject(Object1);
PrintMessageFromObject(Object2);
}
private void PrintMessageFromObject(object obj)
{
if (obj is IPrintMessage)//对象标识符 关键字is 接口标识符
{
IPrintMessage PrintMessage;
PrintMessage = (IPrintMessage)obj;//访问对象接口实现时 先声明一个接口类型的变量 然后将对象类型转换成接口类型
PrintMessage.Print();
}
}
}
private void PrintMessageFromObject(object obj)
{
IPrintMessage PrintMessage;
PrintMessage = obj as IPrintMessage;//对象标识符 关键字as 接口标识符
if (PrintMessage != null)//c#关键字null(空值)
PrintMessage.Print();
}