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Arne Schmitz
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 Posted: Wed Dec 14, 2005 3:44 pm Post subject: Changing the variable of a for loop |
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Does the changing of an iterator variable in a for loop result in undefined
behaviour? For example
for (int i = 0; i < 5; ++i)
i = 6;
Arne
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Jeffrey Schwab
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| Posted: Wed Dec 14, 2005 7:26 pm Post subject: Re: Changing the variable of a for loop |
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Arne Schmitz wrote:
| Quote: | Does the changing of an iterator variable in a for loop result in undefined
behaviour? For example
for (int i = 0; i < 5; ++i)
i = 6;
|
No, but you probably should comment that.
i = 6; // Loop will end on next test.
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vord.fok@gmail.com
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| Posted: Wed Dec 14, 2005 7:27 pm Post subject: Re: Changing the variable of a for loop |
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Undefined behaviour .. mm lets see .
You type in i=6 in the instruction .
the cycle is over and the he reads his for again . the statement says i
< 5 . the answer is i is bigger then 5 and he exit the loop . no
problem .
Why should that give any problems ?
your using this in coalition with an if statement or else there would
be no reason to make that loop in the first place .
that is a good solution if you want to go trough the loop without using
a break .
Greetings
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Thomas Tutone
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| Posted: Wed Dec 14, 2005 7:27 pm Post subject: Re: Changing the variable of a for loop |
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Arne Schmitz wrote:
| Quote: | Does the changing of an iterator variable in a for loop result in undefined
behaviour? For example
for (int i = 0; i < 5; ++i)
i = 6;
|
No, you are free to change that variable in the loop, and the behavior
is well defined. What you've written is equivalent to (leaving aside
variable scope issues):
{
int i = 0;
while (i < 5) {
i = 6;
++i;
}
}
Best regards,
Tom
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