Function & header files

[Umesh]

how to convert a program to a function/macro and put it in a header
file? is there any shortcut method for this?
thanks.

[Richard Heathfield]

Umesh said:

how to convert a program to a function/macro and put it in a header
file?

Don't even try. Instead, find out how to use libraries.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[mark_bluemel]

On 12 Jun, 14:05, Richard Heathfield <[e-mail].i nvalidwrote:

Umesh said:

how to convert a program to a function/macro and put it in a header
file?

Don't even try. Instead, find out how to use libraries.

Now you've done it. If he picks up on this (he may not, as he
generally wants to be spoonfed a direct answer to his question), he'll
now ask "how to use libraries?" and we'll have a heap of "off-topic"
responses...

[Umesh]

How can I convert a function to a macro in general? e.g.

void factorial(int n)
{
long int x=1;
for (int i=1;i<=n;i++)
x*=i;
printf("Factori al of %d = %ld\n",n,x);
}

[Morris Dovey]

Umesh wrote:

| How can I convert a function to a macro in general? e.g.
|
| void factorial(int n)
| {
| long int x=1;
| for (int i=1;i<=n;i++)
| x*=i;
| printf("Factori al of %d = %ld\n",n,x);
| }

Sorry - there is no "general solution". Please re-read Richard's
article.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

[Richard Heathfield]

Umesh said:

How can I convert a function to a macro in general? e.g.

void factorial(int n)
{
long int x=1;
for (int i=1;i<=n;i++)
x*=i;
printf("Factori al of %d = %ld\n",n,x);
}

You'd be better off asking "how can I avoid risking the generation of
incorrect results?"

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[Keith Thompson]

Richard Heathfield <rj*@see.sig.in validwrites:

Umesh said:

>How can I convert a function to a macro in general? e.g.

void factorial(int n)
{
long int x=1;
for (int i=1;i<=n;i++)
x*=i;
printf("Factori al of %d = %ld\n",n,x);
}

You'd be better off asking "how can I avoid risking the generation of
incorrect results?"

He'd be *far* better off asking "How do I use this Usenet thing
without looking like a parasite?".

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[pete]

Umesh wrote:

>
How can I convert a function to a macro in general? e.g.

void factorial(int n)
{
long int x=1;
for (int i=1;i<=n;i++)
x*=i;
printf("Factori al of %d = %ld\n",n,x);
}

A function that declares local variables,
is a poor candidate for conversion to a macro.

/* BEGIN new.c */

#include <stdio.h>

#define factorial(N) \
do { \
n = N; \
x = i = 1; \
while (n >= i) { \
x *= i++; \
} \
printf("Factori al of %d = %ld\n", n, x); \
} while (0)

void (factorial)(int n);

int main(void)
{
long int x = 1, i = 1, n;

factorial(5);
(*factorial)(5) ;
return 0;
}

void (factorial)(int n)
{
long int x = 1, i = 1;

factorial(n);
}

/* END new.c */
--
pete

[Umesh]

// factorial by macro

#include<stdio. h>
#define factorial(n) \
long int x=1; \
for(int i=1;i<=n;i++) \
x*=i; \
printf("Factori al of %d = %ld\n",n,x);\

main()
{
int n;
printf("Enter No.- ");
scanf("%d",&n);
factorial(n);
return 0;
}

[Richard Heathfield]

Umesh said:

// factorial by macro

#include<stdio. h>
#define factorial(n) \
long int x=1; \
for(int i=1;i<=n;i++) \
x*=i; \
printf("Factori al of %d = %ld\n",n,x);\

main()
{
int n;
printf("Enter No.- ");
scanf("%d",&n);
factorial(n);
return 0;
}

foo.c:9: warning: return-type defaults to `int'
foo.c:9: warning: function declaration isn't a prototype
foo.c: In function `main':
foo.c:13: parse error before `long'
foo.c:13: parse error before `int'
foo.c:13: `i' undeclared (first use in this function)
foo.c:13: (Each undeclared identifier is reported only once
foo.c:13: for each function it appears in.)
foo.c:13: warning: statement with no effect
foo.c:13: parse error before `)'
foo.c:13: `x' undeclared (first use in this function)
make: *** [foo.o] Error 1

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.