Divide error during debug

[mudman]

I'm running Visual Studio.NET and am experiencing a problem during debugging
(i assume this will also be the case during normal operation). If the
variable "test" is a double and "denom" a finite integer, the operation test
= 1 / denom; results in test having a value of 0.000000! However, if denom is
also a double, test has the correct value. Dumb question perhaps, but am i
missing something?

[William DePalo [MVP VC++]]

Re: Divide error during debug

"mudman" <mudman@discuss ions.microsoft. com> wrote in message
news:94BBC357-2088-4DA1-881F-D69E095C43A1@mi crosoft.com...[color=blue]
> I'm running Visual Studio.NET and am experiencing a problem during
> debugging
> (i assume this will also be the case during normal operation). If the
> variable "test" is a double and "denom" a finite integer, the operation
> test
> = 1 / denom; results in test having a value of 0.000000! However, if denom
> is
> also a double, test has the correct value. Dumb question perhaps, but am i
> missing something?[/color]

If you have something like this

int denom;
double test;

test = 1 / denom;

then test will be assigned a value of zero (where denom is not 0). That's
because the division happens in integers, it yields a result of 0 and
integer 0 is converted to double 0.

If on the other hand you have an expression that contains integers and
doubles then the integers are promoted to doubles before the division and
assignment happen.

Is that what you see?

Regards,
Will

[mudman]

Re: Divide error during debug

This would indeed explain what i am experiencing, although it is somewhat
illogical- essentially, the expression is being interpreted as:

test = (double)((int)( 1 / denom));

Thanks.
[color=blue]
> If you have something like this
>
> int denom;
> double test;
>
> test = 1 / denom;
>
> then test will be assigned a value of zero (where denom is not 0). That's
> because the division happens in integers, it yields a result of 0 and
> integer 0 is converted to double 0.
>
> If on the other hand you have an expression that contains integers and
> doubles then the integers are promoted to doubles before the division and
> assignment happen.[/color]

[William DePalo [MVP VC++]]

Re: Divide error during debug

"mudman" <mudman@discuss ions.microsoft. com> wrote in message
news:28C9D12A-1933-4350-864E-307D76939CBB@mi crosoft.com...[color=blue]
> This would indeed explain what i am experiencing, although it is somewhat
> illogical- essentially, the expression is being interpreted as:
>
> test = (double)((int)( 1 / denom));[/color]

Is is that, or essentially that?

Your C style cast above

(int)

forces the devision to be done in integers, no? And that zero result is cast
to double.

Why not try

test = (double) 1 / denom;
[color=blue]
> Thanks.[/color]

You are welcome.

Regards,
Will