My switch is not switching

[=?ISO-8859-15?Q?Marian_Aldenh=F6vel?=]

Hi,

To handle a custom protocol over a serial line I am trying to implement
a very small and simple state machine. The states are declared as enum:

enum CommState {
CS_WAIT_FOR_STX,
CS_WAIT_FOR_T,
CS_WAIT_FOR_0,
CS_WAIT_FOR_Key,
CS_WAIT_FOR_ETX
};

I wanted to switch on the current state and handle whatever needs to be
done in that state plus the transition to the next one. However, my
switch() is always falling through to the default case.

I have cut down my code to this nonsensical example:

CommState commState=CS_WAIT_FOR_STX;

if (commState==CS_WAIT_FOR_STX) {
std::cout << "commState==CS_WAIT_FOR_STX" << std::endl;
}

switch (commState) {
CS_WAIT_FOR_STX:
std::cout << "switch-label CS_WAIT_FOR_STX" << std::endl;
break;
default:
std::cout << "default" << std::endl;
}

I would have expected this to output

commState==CS_WAIT_FOR_STX
switch-label CS_WAIT_FOR_STX

But I am getting:

commState==CS_WAIT_FOR_STX
default

What am I doing wrong?

The Compiler is GCC 4.2.3, on Ubuntu 7.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn
http://www.marian-aldenhoevel.de
"Success is the happy feeling you get between the time you
do something and the time you tell a woman what you did."

[Stuart Golodetz]

Marian Aldenhövel wrote:

Hi,

To handle a custom protocol over a serial line I am trying to implement
a very small and simple state machine. The states are declared as enum:

enum CommState {
CS_WAIT_FOR_STX,
CS_WAIT_FOR_T,
CS_WAIT_FOR_0,
CS_WAIT_FOR_Key,
CS_WAIT_FOR_ETX
};

I wanted to switch on the current state and handle whatever needs to be
done in that state plus the transition to the next one. However, my
switch() is always falling through to the default case.

I have cut down my code to this nonsensical example:

CommState commState=CS_WAIT_FOR_STX;

if (commState==CS_WAIT_FOR_STX) {
std::cout << "commState==CS_WAIT_FOR_STX" << std::endl;
}

switch (commState) {
CS_WAIT_FOR_STX:

ITYM case CS_WAIT_FOR_STX:

You've just defined a label there (oops!)

Incidentally, VC++ 2005 warns me when I do this:

warning C4065: switch statement contains 'default' but no 'case' labels
warning C4102: 'CS_WAIT_FOR_STX' : unreferenced label

Have you got all warnings turned on for GCC? It might have something
similar.

Regards,
Stu

std::cout << "switch-label CS_WAIT_FOR_STX" << std::endl;
break;
default:
std::cout << "default" << std::endl;
}

I would have expected this to output

commState==CS_WAIT_FOR_STX
switch-label CS_WAIT_FOR_STX

But I am getting:

commState==CS_WAIT_FOR_STX
default

What am I doing wrong?

The Compiler is GCC 4.2.3, on Ubuntu 7.

Ciao, MM

[Salt_Peter]

On Aug 16, 8:46 am, Marian Aldenhövel <[e-mail]:

Hi,

To handle a custom protocol over a serial line I am trying to implement
a very small and simple state machine. The states are declared as enum:

enum CommState {
CS_WAIT_FOR_STX,
CS_WAIT_FOR_T,
CS_WAIT_FOR_0,
CS_WAIT_FOR_Key,
CS_WAIT_FOR_ETX
};

I wanted to switch on the current state and handle whatever needs to be
done in that state plus the transition to the next one. However, my
switch() is always falling through to the default case.

I have cut down my code to this nonsensical example:

CommState commState=CS_WAIT_FOR_STX;

if (commState==CS_WAIT_FOR_STX) {
std::cout << "commState==CS_WAIT_FOR_STX" << std::endl;
}

switch (commState) {
CS_WAIT_FOR_STX:
std::cout << "switch-label CS_WAIT_FOR_STX" << std::endl;
break;
default:
std::cout << "default" << std::endl;
}

I would have expected this to output

commState==CS_WAIT_FOR_STX
switch-label CS_WAIT_FOR_STX

But I am getting:

commState==CS_WAIT_FOR_STX
default

What am I doing wrong?

The Compiler is GCC 4.2.3, on Ubuntu 7.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonnhttp://www.marian-aldenhoevel.de
"Success is the happy feeling you get between the time you
do something and the time you tell a woman what you did."

Try it like this:

#include <iostream>

namespace state
{
enum Comm {
CS_WAIT_FOR_STX,
CS_WAIT_FOR_T,
CS_WAIT_FOR_0,
CS_WAIT_FOR_Key,
CS_WAIT_FOR_ETX };
}

int main()
{
const state::Comm test = state::CS_WAIT_FOR_STX;

switch( test )
{
case state::CS_WAIT_FOR_STX:
std::cout << "switch-label CS_WAIT_FOR_STX\n";
break;
default:
std::cout << "default state\n";
}
}

[=?ISO-8859-15?Q?Marian_Aldenh=F6vel?=]

Hi,

You've just defined a label there (oops!)

I KNEW it was going to be something really, really dumb. Thank you
very much!

Have you got all warnings turned on for GCC? It might have something
similar.

No, hadn't. Another stupid mistake. Now, compiling with -Wall, I get:

KeyboardHandler.cpp:205: warning: label 'CS_WAIT_FOR_STX' defined but notused

Thank's again.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn
http://www.marian-aldenhoevel.de
"Success is the happy feeling you get between the time you
do something and the time you tell a woman what you did."

[Rolf Magnus]

Marian Aldenhövel wrote:

Hi,

>You've just defined a label there (oops!)

I KNEW it was going to be something really, really dumb. Thank you
very much!

>Have you got all warnings turned on for GCC? It might have something
similar.

No, hadn't. Another stupid mistake. Now, compiling with -Wall, I get:

KeyboardHandler.cpp:205: warning: label 'CS_WAIT_FOR_STX' defined but not
used

Thank's again.

Make it a habit to at least use -ansi -pedantic -Wall -Wextra