usr/lib/learn/C/L30.1a

#print
Write a subroutine named "index(s,c)" which expects two
arguments: the first is a pointer to characters 's' which
points to a null-terminated string, and the second
is a character 'c' which is to be searched for in the
string 's'.  If the character 'c' does not
appear in the string return 0; otherwise return a pointer
to the position of 'c' in the string. Name the program "index.c";
as usual, compile and test it and then type "ready".
#once #create Ref
0
19
0
25
0
#once #create tzaqc.c
char *alpha "abcdefghijklmnopqrstuvwxyz";
main()
{
        extern char *index();
        printf("%d\n", index(alpha, '+'));
        printf("%d\n",index(alpha, 't')-alpha));
        printf("%d\n",index(alpha, 'a')-alpha));
        printf("%d\n",index(alpha, 'z')-alpha));
        printf("%d\n",index("", 'z'));
}
#user
cc tzaqc.c index.o
a.out  >value
#cmp value Ref
#succeed
Try this:

char *index (s, c)
char *s;
{
        for( ; *s; s++)
                if (*s == c)
                        return(s);
        return(0);
}
#log
#next
31.1a 10