String appending

[Selvesteen]

Hello Gurus,

I need to append a sub-string at the start of strings using C. What is
the best way to achieve that?

for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...

Advance thanks for all your help.

[Suman]

Re: String appending

Selvesteen wrote:[color=blue]
> Hello Gurus,
>
> I need to append a sub-string at the start of strings using C. What is
> the best way to achieve that?
>
> for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
> result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...
>
> Advance thanks for all your help.[/color]
<from code posted earlier, by W Roberson, in recent past,
some other thread, "#defines and strings" ...>

/*--BEGIN--*/

#include <stdio.h>

#define PASTE(T1,T2) T1##T2
#define Append(N) (N, PASTE("SSL_",N) )

int main()
{
printf("%s\n", Append("CLASS") );
return 0;
}
/*--END--*/

Does that help?

[Jirka Klaue]

Re: String appending

Suman:[color=blue]
> Selvesteen:[/color]
....[color=blue][color=green]
>> for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
>> result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...[/color][/color]
....[color=blue]
> /*--BEGIN--*/
>
> #include <stdio.h>
>
> #define PASTE(T1,T2) T1##T2
> #define Append(N) (N, PASTE("SSL_",N) )
>
> int main()
> {
> printf("%s\n", Append("CLASS") );
> return 0;
> }
> /*--END--*/
>
> Does that help?[/color]

Most probably not. This is not valid C and shouldn't compile.
And what is the 'N,' in Append(N) for?

#include <stdio.h>

#define APPEND(x) ("SSL_" #x)

int main()
{
printf("%s\n", APPEND(CLASS));
return 0;
}

Jirka

[Suman]

Re: String appending



Jirka Klaue wrote:[color=blue]
> Suman:[color=green]
> > Selvesteen:[/color]
> ...[color=green][color=darkred]
> >> for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
> >> result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...[/color][/color]
> ...[color=green]
> > /*--BEGIN--*/
> >
> > #include <stdio.h>
> >
> > #define PASTE(T1,T2) T1##T2
> > #define Append(N) (N, PASTE("SSL_",N) )
> >
> > int main()
> > {
> > printf("%s\n", Append("CLASS") );
> > return 0;
> > }
> > /*--END--*/
> >
> > Does that help?[/color]
>
> Most probably not. This is not valid C and shouldn't compile.
>[/color]
Which one ?

[Suman]

Re: String appending



Suman wrote:[color=blue]
> Jirka Klaue wrote:[color=green]
> > Suman:[color=darkred]
> > > Selvesteen:[/color]
> > ...[color=darkred]
> > >> for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
> > >> result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...[/color]
> > ...[color=darkred]
> > > /*--BEGIN--*/
> > >
> > > #include <stdio.h>
> > >
> > > #define PASTE(T1,T2) T1##T2
> > > #define Append(N) (N, PASTE("SSL_",N) )
> > >
> > > int main()
> > > {
> > > printf("%s\n", Append("CLASS") );
> > > return 0;
> > > }
> > > /*--END--*/
> > >
> > > Does that help?[/color]
> >
> > Most probably not. This is not valid C and shouldn't compile.
> >[/color]
> Which one ?[/color]
Ah! ha. Hubris! Got it.

[Jirka Klaue]

Re: String appending

Suman:[color=blue]
> Jirka Klaue:[color=green]
>> Suman:[/color][/color]
....[color=blue][color=green][color=darkred]
>> > /*--BEGIN--*/
>> >
>> > #include <stdio.h>
>> >
>> > #define PASTE(T1,T2) T1##T2
>> > #define Append(N) (N, PASTE("SSL_",N) )
>> >
>> > int main()
>> > {
>> > printf("%s\n", Append("CLASS") );
>> > return 0;
>> > }
>> > /*--END--*/
>> >
>> > Does that help?[/color]
>>
>> Most probably not. This is not valid C and shouldn't compile.
>>[/color]
> Which one ?[/color]

PASTE("A", "B") yields "A""B" which is not a valid preprocessing token.

Do you use Microsoft's C-Compiler by any chance?

Jirka

[john_bode@my-deja.com]

Re: String appending



Selvesteen wrote:[color=blue]
> Hello Gurus,
>
> I need to append a sub-string at the start of strings using C. What is
> the best way to achieve that?
>
> for eg : I need to append "SSL"_ before { CLASS, SEED, RANDOM } to get
> result as SSL_CLASS, SSL_SEED, SSL_RANDOM ...
>
> Advance thanks for all your help.[/color]

Slightly different approach from using macros:

#include <stdio.h>

#define MAX_NAME_LEN 10 /* length of longest result */
/* string, not counting */
/* terminator */
#define MAX_NAME_COUNT 3

int main(void)
{
char *prefix="SSL";
char *names[MAX_NAME_COUNT]={"CLASS", "SEED", "RANDOM"};
char results[MAX_NAME_COUNT][MAX_RESULT_LEN+ 1];
int i;

for (i = 0; i < MAX_NAME_COUNT; i++)
{
sprintf(results[i], "%s_%s", prefix, names[i]);
printf("%s\n", results[i]);
}

return 0;
}

[Suman]

Re: String appending



Jirka Klaue wrote:[color=blue]
> Suman:[color=green]
> > Jirka Klaue:[color=darkred]
> >> Suman:[/color][/color]
> ...[/color]
[snipped][color=blue]
>
> PASTE("A", "B") yields "A""B" which is not a valid preprocessing token.
>
> Do you use Microsoft's C-Compiler by any chance?[/color]
Not if my manager's not around :)
But this time, you've hit bull's eye! I did, and ... I apologise for
causing (any/all) confusion for that code.

I checked with gcc and it bit me hard.

[Randy Howard]

Re: String appending

On Fri, 1 Jul 2005 08:46:24 -0500, john_bode@my-deja.com wrote
(in article
<1120225583.988 367.53140@z14g2 000cwz.googlegr oups.com>):
[color=blue]
> Slightly different approach from using macros:
>
> #include <stdio.h>
>
> #define MAX_NAME_LEN 10 /* length of longest result */
> /* string, not counting */
> /* terminator */
> #define MAX_NAME_COUNT 3
>
> int main(void)
> {
> char *prefix="SSL";
> char *names[MAX_NAME_COUNT]={"CLASS", "SEED", "RANDOM"};[/color]

Delete this line:[color=blue]
> char results[MAX_NAME_COUNT][MAX_RESULT_LEN+ 1];[/color]
[color=blue]
> int i;
>
> for (i = 0; i < MAX_NAME_COUNT; i++)
> {[/color]
Delete this line:[color=blue]
> sprintf(results[i], "%s_%s", prefix, names[i]);[/color]

Delete this line:[color=blue]
> printf("%s\n", results[i]);[/color]

Add this line:
printf("%s_%s\n ", prefix, names[i]);[color=blue]
> }
>
> return 0;
> }
>[/color]



--
Randy Howard (2reply remove FOOBAR)

[john_bode@my-deja.com]

Re: String appending



Randy Howard wrote:[color=blue]
> On Fri, 1 Jul 2005 08:46:24 -0500, john_bode@my-deja.com wrote
> (in article
> <1120225583.988 367.53140@z14g2 000cwz.googlegr oups.com>):
>[color=green]
> > Slightly different approach from using macros:
> >
> > #include <stdio.h>
> >
> > #define MAX_NAME_LEN 10 /* length of longest result */
> > /* string, not counting */
> > /* terminator */
> > #define MAX_NAME_COUNT 3
> >
> > int main(void)
> > {
> > char *prefix="SSL";
> > char *names[MAX_NAME_COUNT]={"CLASS", "SEED", "RANDOM"};[/color]
>
> Delete this line:[color=green]
> > char results[MAX_NAME_COUNT][MAX_RESULT_LEN+ 1];[/color][/color]

[Remaining helpful hints snipped]

I thought it *might* be useful to the OP to demonstrate how to keep the
result strings around and save a few cycles later on.

Obviously, I was wrong. In the future I will endeavor to never suggest
anything so old-fashioned and stupid as keeping the results of your
operations around for later use.