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Re: Confused about floats
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Re: Confused about floats


  • Subject: Re: Confused about floats
  • From: Velocityboy <email@hidden>
  • Date: Tue, 5 Oct 2010 08:42:54 -0700

You can, but again this is just being explicit - the compiler bases promotion decisions on type alone, not whether or not an expression is a constant or a variable.

The one important thing to remember is that promotion of assignment is applied *after* the RHS is evaluated, i.e.

float f = 1 /  2;

is equivalent to

float f = (float)( 1 / 2 );

which is zero, since integer division is used.

In that case, it does matter, and either 1.0f / 2, or 1 / 2.0f will give the intended result.


On Oct 5, 2010, at 8:32 AM, Shawn Bakhtiar wrote:

>
>
> :*S
>
> Yes... I see the point. Correct.
>
> For a constant value this is true, in the instance of x = x + 1 (which I see where the error was), where x is a float this makes no difference.
>
> However, for clarity of the OP, x = x + y where y is an int, should be typecast correctly as x = x + (float)y
>
> Personally when I am writing code, I always write as x = x + 1.0 for clarity as well.
>
> Sorry for not understanding the rebuttal :*)
>
>
>> Subject: Re: Confused about floats
>> From: email@hidden
>> Date: Tue, 5 Oct 2010 09:24:13 -0600
>> CC: email@hidden
>> To: email@hidden
>>
>> On Oct 5, 2010, at 9:16 AM, Shawn Bakhtiar wrote:
>>
>>> Did you just call typecasting  "*completely* unnecessary and pointless"...
>>
>> No, I called typecasting an int type to a floating type, in order to add it to a floating type, unnecessary and pointless.
>>
>>> You may be correct in that in Objective-C this may no longer be an issue, as the compiler does your work for you, but that was not an assumption I was making.
>>
>> It's got nothing to do with Objective-C; C has always taken care of that case. What exactly do you think is wrong with x = x + 100 where x is a double?
>>
>> --
>> Scott Ribe
>> email@hidden
>> http://www.elevated-dev.com/
>> (303) 722-0567 voice
>>
>>
>>
>>
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References: 
 >Re: Confused about floats (From: Gregory Weston <email@hidden>)
 >RE: Confused about floats (From: Shawn Bakhtiar <email@hidden>)
 >Re: Confused about floats (From: Scott Ribe <email@hidden>)
 >RE: Confused about floats (From: Shawn Bakhtiar <email@hidden>)
 >Re: Confused about floats (From: Scott Ribe <email@hidden>)
 >RE: Confused about floats (From: Shawn Bakhtiar <email@hidden>)

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