On Mon, 12 May 2008 16:42:20 +0000, Erik Wikström wrote:
> On 2008-05-12 17:59, bintom wrote:
>> On May 12, 8:23 pm, Lionel B <m...@[EMAIL PROTECTED]
> wrote:
>>> On Mon, 12 May 2008 08:09:47 -0700, bintom wrote:
>>> > I ran the following simple code in C++ and got unexpected results:
>>>
>>> > float f = 139.4;
>>> > cout << f;
>>>
>>> > Output:
>>> > 139.399994;
>>>
>>> > if( f == 139.4)
>>> > cout << "Expected result";
>>> > else
>>> > cout << "Unexpected result";
>>>
>>> > Output:
>>> > Unexpected reult
>>>
>>> [...]
>>>
>>> > Doesn't this look bad on C++'s resume?
>>>
>>> No, it looks bad on *your* resume ;-)
>>>
>>> http://www.para****ft.com/c++-faq-lite/newbie.html#faq-29.16
>
> Please do not quote signatures.
>
>> Thanks Lionel for directing me to the link, but my question remains
>> unanswered. Should it be a computer science issue as it says on the
>> site, VB should've produced a similar (inaccurate) result. I'm just
>> trying to defend my resume.
>
> You are comparing apples to pears, f is a float while 13.4 is a double
> (an advice, always turn up the warning levels and fix as many of them as
> you can), try this code and see what it does:
>
> #include <iostream>
>
> int main()
> {
> float f = 139.4f;
> std::cout << f << "\n";
>
> if( f == 139.4f)
> std::cout << "Expected result\n";
> else
> std::cout << "Unexpected result\n";
> }
On my system (compiler GCC 4.1.2) with
float f = 139.4;
and compiled with:
g++ -std=c++98 -pedantic -Wall -Wextra
I get no warnings and the output is 'Expected result'. Should the
compiler warn if there's an implicit conversion? Or only if it results in
loss of precision?
--
Lionel B
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