Please help

[Pawan Arora]

Why the following programme was showing me the output 5

class C{
public static void main(String args[]) {
int a = 1;
a += ++a + a++;
System.out.print(a);
}}

as far as the rules of pre increment, the value is incremented before being assigned and in post increment, the value is assigned to variable before being used. So why the output was 5 not 6?
Another agony,
Why the following programme compiling successfully?

interface I {           //1
  public class Inner {   ///2
          
          Inner ( ) {
                  System .out . println ( "Inner Created" ) ;
          }
  };
};

Please help with suitable reason. Thanks in advance for help.

[Steve Luke]

Originally posted by Jack back:
Why the following programme was showing me the output 5

class C{
public static void main(String args[]) {
int a = 1;
a += ++a + a++;
System.out.print(a);
}}

as far as the rules of pre increment, the value is incremented before being assigned and in post increment, the value is assigned to variable before being used.

The post increment happens AFTER evaluating the value of the variable, and BEFORE assignment to the left hand side. The order is this:
a = 1;
EVAL:
Right Side = a = 1; [from a+=]
++a -> 1+a -> 2; [from ++a]
Right Side = 1 + 2; [from + ++a]
a++ -> a -> 2; [from a++]
Right Side = 1 + 2 + 2; [from + a++]
a++ -> a + 1 -> 3; [from a++]
Right Side = 5; [from a+= ++a + a++]
ASSIGN:
a = Right Side = 5;

So why the output was 5 not 6?
Another agony,
Why the following programme compiling successfully?

Because you are allowed to have public static inner classes inside an interface...

[Rob Spoor]

"Jack back",

Please read your private messages regarding an important announcement.

Thank you,

Rob

[Campbell Ritchie]

. . . and, in future, please use a title which tells us what the thread is about; "Please Help" isn't very useful.

[Pawan Arora]

Thanks Steve, thanks for your reply.
I still have one problem, why the a+= is not like a=a+1??
[ October 12, 2008: Message edited by: Jack Black ]

[Bear Bibeault]

"Jack Black", did you check your private messages as Rob requested? Please check again.

[Rene Larsen]

Originally posted by Jack Black:
Thanks Steve, thanks for your reply.
I still have one problem, why the a+= is not like a=a+1??

a += means a = a + x

[Rob Spoor]

Originally posted by Bear Bibeault:
"Jack Black", did you check your private messages as Rob requested? Please check again.

Indeed. Unless you are a short pudgy actor / singer, either your name is not allowed or you need to show us that Jack Black really is your name.

[Jacob Steingart]

No offense, but this sounds like a homework question... am I the only one thinking this?

[Steve Luke]

Originally posted by Jacob Steingart:
No offense, but this sounds like a homework question... am I the only one thinking this?

I think it is a question from homework - yes, but he isn't asking to have it done for him. He is asking for understanding the output, which I think is appropriate.

If it isn't homework (or studying for some test) then the correct answer is: Don't do that!