Differences between C++ and Java with this-pointer

[Rasti]

Hello,



I am trying to translate a C++ script to Java. Are there any differences
between the C++ this-pointer and the Java this-pointer?



Thank you

Flo

 

[Victor Bazarov]

I am trying to translate a C++ script to Java. Are there any differences
between the C++ this-pointer and the Java this-pointer?

In Java 'this' is NOT a pointer. There are no pointers in Java.

And, if you have questions on Java, try a Java newsgroup.

Victor

 

[Joe Gottman]

In Java 'this' is NOT a pointer. There are no pointers in Java.

And, if you have questions on Java, try a Java newsgroup.

Personally, I think that a question about the similarities and
differences between C++ and Java is on-topic for either C++ or Java
newsgroups. To answer the OP's question, in C++ 'this' is a pointer and in
Java 'this' is a reference, because Java doesn't have pointers. However,
the C++ 'this' pointer is rather strange, because it cannot be reassigned
and cannot be null. It probably should have been a reference. As I
understand it, the main reason it wasn't is because it was invented before
references were.

Joe Gottman

 

[lilburne]

However,
the C++ 'this' pointer is rather strange, because it cannot be reassigned
and cannot be null.

void func(A& a);


A* aptr = 0;
func(*aptr);

I think you'll find that within func a's this pointer will
be null.

 

[Pete Becker]

In Java 'this' is NOT a pointer. There are no pointers in Java.

There are no pointers, but there is a NullPointerException.

 

[Joe Gottman]

void func(A& a);


A* aptr = 0;
func(*aptr);

I think you'll find that within func a's this pointer will
be null.

Derefencing a null pointer, as you do when you call func(*aptr) results
in undefined behavior. You might have a's this pointer null inside the
function call, or you might have a core dump before func is even called.

Joe Gottman