[fpc-devel]urgent: double + integer question/types in calculations

[Konstantin Muenning]

On Wed, 6 Feb 2002, Michael Van Canneyt wrote:

>On Wed, 6 Feb 2002, raoul s wrote:
>
>> I have "a" as double and "b" as integer.
>> 1) how may I say "a := b" in pascal. "a" on left and
>> "b" on the
>> right.
(snip)

>The compiler does the typeconversion.
>
>
>> 2)can one way would be?:
>> a := b + 0.0;
>
>You can do that but it is not necessary.
>
>>
>> i like to keep the results for a as double.
>
>An assignment cannot change the type of the left side.

By the way, about types in calculations and assignments. What types are
used in FPC for doing the actual calculations. I have the experience with
Borland Pascal that I have to be carefull in some cases. P.ex.

VAR
 a:Integer;b,c:Word;
:
a:=b-c;
:

BP would use Word for the calculation so if c>b there would be (I think) a
range check error (if enabled). Changing it to

a:=-c+b;

would make BP to use Integer or LongInt (I'm not shure which) and the
result would be OK. In my opinion the calculation should base on the
result type, not on the types on the right side but that's what BP is
doing. hat does FPC?

Have a nice day,
Konstantin Münning              ,,,
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