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Re: Unnecessary Boolean Warning
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Re: Unnecessary Boolean Warning


  • Subject: Re: Unnecessary Boolean Warning
  • From: Graham Cox <email@hidden>
  • Date: Thu, 04 Aug 2011 10:56:17 +1000

On 04/08/2011, at 1:52 AM, Jean-Daniel Dupas wrote:

> One important difference for instance is that if you write if (a() & b()), both a() and b() will always be executed, while if you write if (a() && b()), b() will be executed only if a() is true.


The C language doesn't make any guarantees about that. While this optimisation is to be expected, the order of execution (left to right) and the optimisation (b not executed) is implementation dependent.

This is a classic question for coding job interviews.

--Graham


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    • Re: Unnecessary Boolean Warning
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References: 
 >Unnecessary Boolean Warning (From: Dale Miller <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Charles Srstka <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Dale Miller <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Scott Ribe <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Thomas Davie <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Scott Ribe <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Thomas Davie <email@hidden>)
 >Re: Unnecessary Boolean Warning (From: Jean-Daniel Dupas <email@hidden>)

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