classinheritance.java

Java程序

class A
{int a1=1;
public int a2=2;
protected int a3=3;
private int a4=4;
int geta4()
 {return a4;
 }
}
class B extends A
{int b=5;
int sum()
 {return a1+a2+a3+geta4()+b;
 }
} 
class ClassInheritance
{public static void main(String args[])
 {A aa=new A();
 System.out.println("A:"+aa.a1+"\t"+aa.a2+"\t"+aa.a3+"\t"+aa.geta4());
 B bb=new B();
 System.out.println("B:"+bb.a1+"\t"+bb.a2+"\t"+bb.a3+"\t"+bb.geta4()+"\t"+bb.b+"\t"+bb.sum());
 }
}