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size of a variable in bits

 
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size of a variable in bits
dejabu18
27 Oct, 2006 - 02:26 AM
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hi guys I have some problems whit this function I need to write a function than can return the numbers of bits using for coding a short int variable, I wrote this

CODE
int taille_short(){
    int r=16;
    for(int i=0;i>r;i++)
    {
             return i;
            
    }
}


CODE
int taille_short(){
    int r=16;
    for(int i=0;i>r;i<<1)
    {
             return i;
            
    }
}



can you tell me what you think , I have some problem with the binary operators and whow thy works

thanks
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NyeNye
RE: Size Of A Variable In Bits
27 Oct, 2006 - 02:32 AM
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you just measure or count how many indexs on your ouput....

just a suggestion how bout converting int to a string type then strlen

or if you are using string.h you could use <Strtname>.length()

try for this
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gregoryH
RE: Size Of A Variable In Bits
29 Oct, 2006 - 04:57 AM
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QUOTE(NyeNye @ 27 Oct, 2006 - 03:32 AM) *

you just measure or count how many indexs on your ouput....

just a suggestion how bout converting int to a string type then strlen

or if you are using string.h you could use <Strtname>.length()

try for this


Would there be anything wrong with using the sizeofoperator/function?

eg

short int bitsz = sizeof(char) * 8 ; // sizeof returns bytes... 8 bits in byte.. right?

This post has been edited by gregoryH: 29 Oct, 2006 - 04:58 AM
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Xing
RE: Size Of A Variable In Bits
29 Oct, 2006 - 05:56 AM
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QUOTE(gregoryH @ 29 Oct, 2006 - 06:27 PM) *
8 bits in byte.. right?

Not necessarily. C++ standard says that byte has atleast 8 bits.
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gregoryH
RE: Size Of A Variable In Bits
29 Oct, 2006 - 05:59 AM
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QUOTE(Xing @ 29 Oct, 2006 - 06:56 AM) *

QUOTE(gregoryH @ 29 Oct, 2006 - 06:27 PM) *
8 bits in byte.. right?

Not necessarily. C++ standard says that byte has atleast 8 bits.

Trust a committee to turn a hrose into a camel....

Sort of goes against the traditional meaning of a byte...

Thanks Xing.. i'll go give them a blast
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Xing
RE: Size Of A Variable In Bits
29 Oct, 2006 - 06:15 AM
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If you want to find out how many bits are there in a byte in your implementation then use CHAR_BIT macro which is defined in <climits>.
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gregoryH
RE: Size Of A Variable In Bits
29 Oct, 2006 - 06:21 AM
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QUOTE(Xing @ 29 Oct, 2006 - 07:15 AM) *

If you want to find out how many bits are there in a byte in your implementation then use CHAR_BIT macro which is defined in <climits>.

so I should have used short int bitsz = sizeof(char) * CHAR_BIT

I did a quick look into wikipedia on the humble byte....

Seems it has varied over time from 3 bits up to 12, and with the wide character and unicode characters it may yet have an upgrade...

This post has been edited by gregoryH: 29 Oct, 2006 - 06:23 AM
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