Hello everyone,


The compile error of the following code is,

foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
'_'
foo.cpp(7) : error C2065: '_' : undeclared identifier
foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'

I do not know why there is errors. I think in MERGE macro, the value
of parameter a is hello and the value of parameter b is world in my
case, and I defined hello_world to "H E L L O", it should be fine...

Any ideas?

#define MERGE(a,b)  a ## _ ## b
#define hello_world "H E L L O"

int foo()
{
char* p0;
p0 = MERGE("hello", "world");

return 0;
}

thanks in advance,
George

George2 wrote:
> Hello everyone,
>
>
> The compile error of the following code is,
>
> foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
> '_'
> foo.cpp(7) : error C2065: '_' : undeclared identifier
> foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'
>
> I do not know why there is errors. I think in MERGE macro, the value
> of parameter a is hello and the value of parameter b is world in my
> case, and I defined hello_world to "H E L L O", it should be fine...
>
No, a is "hello" and b is "world" so your macro produces "hello"_"world".

--
Ian Collins.

On Nov 26, 2:10 pm, George2 <george4acade...@yahoo.com> wrote:
> Hello everyone,
>
> The compile error of the following code is,
>
> foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
> '_'
> foo.cpp(7) : error C2065: '_' : undeclared identifier
> foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'
>
> I do not know why there is errors. I think in MERGE macro, the value
> of parameter a is hello and the value of parameter b is world in my
> case, and I defined hello_world to "H E L L O", it should be fine...
>
> Any ideas?
>
>

> #define MERGE(a,b)  a ## _ ## b
> #define hello_world "H E L L O"
>
> int foo()
> {
>         char* p0;
>         p0 = MERGE("hello", "world");

~~~~~~~~~~~~~~~~~~~~~~~~MERGE(hello,world);
>
>         return 0;}
>
> 

>
> thanks in advance,
> George