Noobie question about Switch

[Aristotelis E. Charalampakis]

Hi all, this is a newbie question :-)

I was wondering if there was a way to use the switch statement in a manner
that each case statement includes more that a simple value. i.e.:


switch ( myFloat )
{

case >0: // ??? how do i write this ???

// execute if myfloat >0

break;

case 0:

// execute if myfloat ==0

break;

default:

// you got the idea
}

TIA
Aristotelis

[lallous]

Re: Noobie question about Switch

Hello,

"Aristoteli s E. Charalampakis"
<aristotelis_ch aralampakis@REM OVEMEhotmail.co m> wrote in message
news:bshe3m$2vb i$1@ulysses.noc .ntua.gr...[color=blue]
> Hi all, this is a newbie question :-)
>
> I was wondering if there was a way to use the switch statement in a manner
> that each case statement includes more that a simple value. i.e.:
>
>
> switch ( myFloat )
> {
>
> case >0: // ??? how do i write this ???
>
> // execute if myfloat >0
>
> break;
>
> case 0:
>
> // execute if myfloat ==0
>
> break;
>
> default:
>
> // you got the idea
> }
>
> TIA
> Aristotelis
>
>[/color]

You can use if/else if/else combos or some sort of control table of your
design:
float range[3*2] = { 0.1, 0.9, 1, // if greater than 0.1 and below 0.9 then
integer i = 1
1.1, 2.1, 2}; // if 1.1 and 2.1 then 2, etc..

--
Elias

[Aristotelis E. Charalampakis]

Re: Noobie question about Switch

So it is not possible to write something like
"case >0" ?

Can it be written in the form

switch ( TRUE )
case myFloat>0:
etc?

In VB I can write something like this:

select case myFloat
case 2 , 3
'Do something
case Is > 4
'do something else
case else
'default
end select

Or

select case True
case myFloat>4
'Do something
case myFloat<0
'do something else
case else
'default
end select

Is there a way to implement the above with the switch statement?

TIA,
Aristotelis

"lallous" <lallous@lgwm.o rg> wrote in message
news:bshe9m$d61 h6$1@ID-161723.news.uni-berlin.de...[color=blue]
> Hello,
>
> "Aristoteli s E. Charalampakis"
> <aristotelis_ch aralampakis@REM OVEMEhotmail.co m> wrote in message
> news:bshe3m$2vb i$1@ulysses.noc .ntua.gr...[color=green]
> > Hi all, this is a newbie question :-)
> >
> > I was wondering if there was a way to use the switch statement in a[/color][/color]
manner[color=blue][color=green]
> > that each case statement includes more that a simple value. i.e.:
> >
> >
> > switch ( myFloat )
> > {
> >
> > case >0: // ??? how do i write this ???
> >
> > // execute if myfloat >0
> >
> > break;
> >
> > case 0:
> >
> > // execute if myfloat ==0
> >
> > break;
> >
> > default:
> >
> > // you got the idea
> > }
> >
> > TIA
> > Aristotelis
> >
> >[/color]
>
> You can use if/else if/else combos or some sort of control table of your
> design:
> float range[3*2] = { 0.1, 0.9, 1, // if greater than 0.1 and below 0.9[/color]
then[color=blue]
> integer i = 1
> 1.1, 2.1, 2}; // if 1.1 and 2.1 then 2,[/color]
etc..[color=blue]
>
> --
> Elias
>
>[/color]

[Ron Natalie]

Re: Noobie question about Switch


"Aristoteli s E. Charalampakis" <aristotelis_ch aralampakis@REM OVEMEhotmail.co m> wrote in message[color=blue]
> In VB I can write something like this:
>[/color]
We're not in VB anymore.
[color=blue]
> select case myFloat
> case 2 , 3[/color]
In C/C++:
case 2: case 3:

There's no way to do the relationals directly. You could do something like:

switch(i) {
case 2:
case 3:
...

default:
if(i > 10) { ...

You can't do switch with floats at all. The arg has to be an integer or
enum type.

[Rolf Magnus]

Re: Noobie question about Switch

Aristotelis E. Charalampakis wrote:
[color=blue]
> Hi all, this is a newbie question :-)
>
> I was wondering if there was a way to use the switch statement in a
> manner that each case statement includes more that a simple value.
> i.e.:
>
>
> switch ( myFloat )[/color]

You cannot use switch/case on floating point values, only integral
values.
[color=blue]
> {
>
> case >0: // ??? how do i write this ???
>
> // execute if myfloat >0
>
> break;
>
> case 0:
>
> // execute if myfloat ==0
>
> break;
>
> default:
>
> // you got the idea
> }[/color]

There is no way to do that. Just use if:

if (myFloat == 0)

// execut if myFloat == 0

else if (myFloat > 0)

// esecute if myFloat > 0

else

// you got the idea

Btw: testing floating point values for equality is most often a bad idea

[Aristotelis E. Charalampakis]

Re: Noobie question about Switch

Thank you all. I will stick to the if / else combos.
[color=blue]
> Btw: testing floating point values for equality is most often a bad idea[/color]

Yes, it is a bad idea. I am not noobie in general, just in C++.

Yet, I have persuaded myself to write some dlls (mostly math stuff) in C++,
so that I get to know it. Some other dlls are in Visual Fortran 6.5, the gui
in VB.

Aristotelis.

[Chris Mantoulidis]

Re: Noobie question about Switch

"Aristoteli s E. Charalampakis" <aristotelis_ch aralampakis@REM OVEMEhotmail.co m> wrote in message news:<bshe3m$2v bi$1@ulysses.no c.ntua.gr>...[color=blue]
> Hi all, this is a newbie question :-)
>
> I was wondering if there was a way to use the switch statement in a manner
> that each case statement includes more that a simple value. i.e.:[/color]

A way of doing it (just as tiring as if-else though) is:

switch (myFloat > 0) {
case true: blah blah; break; //myfloat > 0
case false: switch (myFloat == 0) {
case true: blah blah; break; //myfloat == 0
case false: blah blah; break; //myfloat < 0
}
break;
}