Multiple expressions in a SWITCH STATEMENT

[jimineep]

I am trying to do a switch statement which analyses multiple expression:

int main(){

        char str1[] = "H"; 
        char str2[] = "B"; 



        switch ( * str1, * str2 ){


        case 'H''B':
                printf("%s","YUP");
                break;

        case 'B''B':
                printf("%s","NOPE");
                break;

        }

        printf("%s", str1 );

}

Is this possible? I am getting errors compiling:

JAMESP>cc test2

        case 'H''B':
................^
%CC-E-NOCOLON, Missing ":".
at line number 21 in file $1$DGA101:[JAMESP.SMP.26856]TEST2.C;17

        case 'B''B':
................^
%CC-E-NOCOLON, Missing ":".
at line number 25 in file $1$DGA101:[JAMESP.SMP.26856]TEST2.C;17

But its not throwing me out for passing 2 expressions to the switch statement...which leads me to believe this may well be possible....

Cheers,

 

[Salem]

> But its not throwing me out for passing 2 expressions to the switch statement.
That's just the comma operator.
The value you're actually switching on is *str2

The rest is not possible using normal cases.


--
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.

 

[jimineep]

Ahh bugga. Cheers!

 

[cjo9900]

You could set up Macros to pass to the switch which combine the two values into one.

e.g.

/* combine two bytes into one uint16 for compare */
#define EVENT(a,b) ((uint16)(a<<8 & b))

then call the switch with the macro

switch(EVENT(*str1,*str2))
{
case EVENT('B','H,):
....

This we use for our software which uses 6 bits to store a resource and 10 bits a feature in that resource, stored over two bytes not consecutive in a message between components.
With enums setup for the resource IDs and features.