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From: bob@nospam.com
Subject: Re: Ada and Java. different behaviour. casting long to int problem.
Date: 1999/06/17
Message-ID: <7kbv64$2t6@drn.newsguy.com>#1/1
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Newsgroups: comp.lang.ada,comp.lang.java.programmer
Date: 1999-06-17T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <37696EAB.E2226E2A@averstar.com>, Tucker says...
>
 
>> Huh? This high level overflow check may not be terribly efficient but
>> it is easy enough.
>
>It is straightforward if all you have is an assignment with
>a single operation.  However, potentially-overflowing arithmetic
>can occur anywhere, including in things like "i++" where significant
>rewriting would be required to insert a check.

Not only that, what about intermmediate generated results?

as in 

A = B + ( C + D)

the result of C+D must be stored somewhere in a register or wherever the
compiler decides. (I am assuming no optimization, and this is just
an example).

So, if the programmer needs to check for oveflow by hand (which is 
a silly solution if I heared of one), then the programmer needs 
to start writing the above like this:

i = C + D
// add code to check that i not overflow
A = B + i
//add code to check that A did not overflow.


Now, with a language that enable expceptions on overflow, I can write

-------------------------------
try
{
  A = B + ( C + D)
}catch(OverFLowException e)
{
   print("hay, watch out, you have a bug on line " + r.printLineNumber()");
   print("please fix your data type, or do something about it");
   // here I can either throw() the expection again, or ignore it
   // but at least I knew about it
}
-----------------------------------
 

bob