Abstract Class

Abstract Classes
Example
abstractclass Stream
{
   public abstract void Write(char ch);
   public void WriteString(string s)
 {
  foreach (char ch in s) Write(s);
 }
}
class File : Stream
{
 public overridevoid Write(char ch) {... write ch to disk...}
}
Note
•Abstract methods do not have an implementation.
•Abstract methods are implicitly virtual.
•If a class has abstract methods it must be declared abstractitself.
•One cannot create objects of an abstract class.