K&R2, page 106 <strcmp>

[arnuld]

I am suing the strcmp function from K&R2, page 106 which is used here:

http://clc-wiki.net/wiki/K%26R2_solutions:Chapter_5:Exercise_4

I only changed the name to avoid confusion with real strcmp. K&R2 says:
it returns < 0, if s <t, 0 if s== t, 0 if s t.

but I have found, it returns < 0 if s t and vice-versa.


int my_strcmp( char* s, char* t )
{
for(; *s == *t; ++s, ++t )
{
printf("*s = %c\n", *s);
printf("*t = %c\n", *t);

if( *s == '\0' )
{
return 0;
}
}

return *s - *t;
}



int main(void)
{
char s[] = "it is ok";
char t[] = "nope";

printf("compari ng <%swith <%s= %d\n", s, t, my_strcmp( s, t ));

return 0;

}

=========== OUTPUT ============
/home/arnuld/programs/C $ gcc -ansi -pedantic -Wall -Wextra 5-5.c
/home/arnuld/programs/C $ ./a.out
comparing <it is okwith <nope= -5
/home/arnuld/programs/C $


--

http://lispmachine.wordpress.com/

Please remove capital 'V's when you reply to me via e-mail.

[WANG Cong]

Re: K&amp;R2, page 106 &lt;strcmp&g t;

arnuld wrote:

I am suing the strcmp function from K&R2, page 106 which is used here:
>

http://clc-wiki.net/wiki/K%26R2_solutions:Chapter_5:Exercise_4

>
>
I only changed the name to avoid confusion with real strcmp. K&R2 says:
it returns < 0, if s <t, 0 if s== t, 0 if s t.
>
but I have found, it returns < 0 if s t and vice-versa.
>
>
int my_strcmp( char* s, char* t )
{
for(; *s == *t; ++s, ++t )
{
printf("*s = %c\n", *s);
printf("*t = %c\n", *t);
>
if( *s == '\0' )
{
return 0;
}
}
>
return *s - *t;
}
>
>
>
int main(void)
{
char s[] = "it is ok";
char t[] = "nope";
>
printf("compari ng <%swith <%s= %d\n", s, t, my_strcmp( s, t ));
>
return 0;
>
}

's' is definitely less than 't' here.

--
Hi, I'm a .signature virus, please copy/paste me to help me spread
all over the world.