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K&R2, page 106 <strcmp>

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

http://clc-wiki.net/wiki/K%26R2_solu...r_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("comparing <%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 $
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Apr 10 '08 #1
1 1284
arnuld wrote:
I am suing the strcmp function from K&R2, page 106 which is used here:

http://clc-wiki.net/wiki/K%26R2_solu...r_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("comparing <%swith <%s= %d\n", s, t, my_strcmp( s, t ));

return 0;

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

--
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all over the world.
Apr 10 '08 #2

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