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Posted by Lawrence on 01/05/08 10:56
On Jan 3, 2:24 pm, Gordon <gordon.mc...@ntlworld.com> wrote:
> On Jan 3, 5:51 am, Lawrence <lawb...@gmail.com> wrote:
>
>
>
> > On Jan 3, 10:34 am, Michael Fesser <neti...@gmx.de> wrote:
>
> > > .oO(Lawrence)
>
> > > >hi all, while im computing large values the variable value gets
> > > >rounded off to the next higher value .How do we stop or prevent this
> > > >happening.
>
> > > How large is "large"? What about a code example?
>
> > > Micha
>
> > $a=$b+$c+$d
> > where $b=99999999999999
> > $c=99999999999999
> > $d=99999999999999
>
> The problem you are running into is integer overflow. a 32 bit
> integer can hold values of -~ 2 billion to +~2 billion, or 0 - ~4
> billion depending on whether or not it is a signed integer. Your sum,
> while the inputs are integers, will result in an answer that is too
> big to fit into an integer. PHP has dynamic types so it will switch
> to a floating point representation in this case. Floating point
> numbers cannot exactly represent some numbers, just like you can't
> represent 1/3 in decimal. Instead, the floating point result will
> contain the closest approximation to the actual number instead.
>
> In this case, what you need is not a floating point number, but what
> is called a bignum instead. Bignums chain smaller integers, or
> strings depending on implementation, together in order to represent
> larger values. PHP provides a BCMath extension that includes support
> for bignums, look at the BCMath documenatation on php.net.
thanx all of u,problem got solved by using bcadd
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