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endless loop

 
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endless loop
amitdhar
post 5 Sep, 2008 - 01:33 AM
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CODE

for(int i=1; i>0; i++)
{
}


According to me the above loop is NOT an example of endless loop, because as i is declared int when it crosses the maximum range of int it will give error and will stop.
But while executing it works as an endless loop, after it reaches the int limit, the i value once again starts automaticaly from 1, once again.
Could you plz explain whats wrong in my logic?
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RedSonja
post 5 Sep, 2008 - 04:58 AM
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That is amusing. I would have expected an overflow exception of some kind. Anyway, it overflowed, like the clock when it crosses midnight, lost the big part, and started at 0 again. I guess you were just lucky you did not overflow into something important.

To be really infinite, just do

while ()

I think that would do the trick. In fact I have one of those running somewhere. Wonder if it's still going? No, it does a break when an interrupt comes.
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baavgai
post 5 Sep, 2008 - 05:30 AM
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When it flips, it goes negative.

e.g.
java

int last=-1;
int i;
for(i=1; i>0; i++) {
	last = i;
}
System.out.println("last = " + last);
System.out.println("i = " + i);


Results:
CODE

last = 2147483647
i = -2147483648


This post has been edited by baavgai: 5 Sep, 2008 - 05:32 AM
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1lacca
post 5 Sep, 2008 - 05:32 AM
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while(){} is not valid in Java, it needs an expression, so it should look-like this: while(true){} Also, in Java integer types can overflow, they won't overwrite anything, it's in the definition of the language. Java is not as brave as C/C++.

amithdar: Are you sure you are running your program correctly?
Dam, baavgai beat me to it, and his solution is nicer.
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