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]

Selvesteen wrote:

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.

<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]

Suman:

Selvesteen: ....

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

.... /*--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?

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]

Jirka Klaue wrote:

Suman:

Selvesteen:

...

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

...

/*--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?

Most probably not. This is not valid C and shouldn't compile.

Which one ?

[Suman]

Suman wrote:

Jirka Klaue wrote:

Suman:

Selvesteen:

...

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

...

/*--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?

Most probably not. This is not valid C and shouldn't compile.

Which one ?

Ah! ha. Hubris! Got it.

[Jirka Klaue]

Suman:

Jirka Klaue:

Suman: ....

> /*--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?

Most probably not. This is not valid C and shouldn't compile.

Which one ?

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]

Selvesteen wrote:

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.

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]

Jirka Klaue wrote:

Suman:

Jirka Klaue:

Suman:

...

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

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

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]

On Fri, 1 Jul 2005 08:46:24 -0500, jo*******@my-deja.com wrote
(in article
<11*********************@z14g2000cwz.googlegroups. com>):

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"};
Delete this line: char results[MAX_NAME_COUNT][MAX_RESULT_LEN+1]; int i;

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

return 0;
}

--
Randy Howard (2reply remove FOOBAR)

[john_bode]

Randy Howard wrote:

On Fri, 1 Jul 2005 08:46:24 -0500, jo*******@my-deja.com wrote
(in article
<11*********************@z14g2000cwz.googlegroups. com>):

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"};

Delete this line:

char results[MAX_NAME_COUNT][MAX_RESULT_LEN+1];

[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.