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In crement-Why is 'a' jumping to 102 instead of 101?

 
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I have a puzzle on my hands: on Item#3 of the attached java file
the 'a' is jumping to 102 when it should be at 101. The output
file (Word) is also attached to this e-mail.
Thank you for your help.
Charles.

 
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Charles,
After step 1 a equals 100 and b equals 101.
But in step 3 b gets incremented to 102 before the new result is assigned to a.
Make sense?
[ February 27, 2004: Message edited by: Howard Kushner ]
 
Charles Keller
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Howard,
You are right, b is at 102 and obviously a follows b at 102.
Thank you Howard, your help is very much appreciated.
Charles.
 
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One interesting thing you might want to figure out is:

First, expand that nasty little += operator. Keep in mind += (like =) is right-associative, so when it is expanded the i is replaced with the value of i before any other evaluation takes place:

(Another code snippet that you might find helpful to run is:

The result after this snippet runs? x is { 5, 0 } and i is 0.)
Because the + operator is right associative, the right operand is evaluated first. The explicitly paranthesized version of the above statement is:

So the expression is evaluated (steps explicitly shown):

Voila.
The thing to keep in mind is that with left-associative operators like = and +=, the leftmost operands are evaluated first and all expressions are replaced. With right-associative operators like +, the rightmost operands are evaluated first and all expressions replaced.
Oh yea, I couldn't leave without this little gem (language lawyers will find this delightful). The following two statements are both compilable and equivalent:

Boggles the mind, don't it?
sev
[ March 01, 2004: Message edited by: sever oon ]
 
Charles Keller
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Thank you sever for your interesting posting re. += bugger. I certainly
will try it out.
I have another question re. Increment & Decrement including prefix and postfix. I tried to make a truth table and I wonder if I got it right or whether there are mistakes in it. So I sending you as attachment the following documents:


I am sorry, Sever, but it looks like the Excel spreadsheet is all screwed up.
Thank you for your help.
Charles.
 
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