Problems in Inheritence

[deepu Bhalotia]

This question has been given in http://www.danchisholm.net/july21/mybook/chapter11/exam1ans.html

Question 2
Suppose that the superclass constructor invocation, "super(argumentListopt);", appears explicitly in a subclass constructor. If a compile-time error is to be avoided then the arguments for the superclass constructor invocation, "super(argumentListopt);", can not refer to which of the following?

a. Static variables declared in this class or any superclass.
b. Instance variables declared in this class or any superclass.
c. Static methods declared in this class or any superclass.
d. Instance methods declared in this class or any superclass.
e. The keyword this.
f. The keyword super.


Can anybody explain it with an Example....

Thanks,
Deepak

(Hopefully fixed the link...)
[ May 10, 2005: Message edited by: Barry Gaunt ]

[Srinivasa Raghavan]

A member variable or a method or reference of "this" cannot be passed to the super class constructor because all these things gets initilized only after all the calls to the constructors gets completed.

[deepu Bhalotia]

can you please make it more clearer...

This question is teasing me for a long time...

Thanks,
Deepak

[Srinivasa Raghavan]

Deepu,

  
class parent 
{
  parent ( int d )
  {}
}
 
public class childtst extends parent
{
 int j;
 childtst ()
 { 
   super ( getVal() );
   j = 10;
 }
 
 public int getVal() { return j;}
}

In the above code when the child class constructor is invoked it calls the superclass constructor explicitly and passing a member variable of the current class as a parameter to the constructor. The members gets initilized only after the call to the constructor is over, but if you see in the code the call to the constructor is not completed but the member variable is accessed.
HTH.

[amit taneja]

the answer is i think b,d, e...

is i m rt ?

[Soni Prasad]

and what about keyword super???

[deepu Bhalotia]

Answer is

1. B
2. D
3. E
4. F


Thanks,
Deepak