K&R 2.5 solution modification to output location/value of matches between strings

Question

K&R 2.5 asks: Write the function any(s1,s2), which returns the first location in the string s1 where any character from the string s2 occurs, or -1 if s1 contains no characters from s2. (The standard library function strpbrk does the same job but returns a pointer to the location.)

Using the first solution given here (http://clc-wiki.net/wiki/K%26R2_solutions:Chapter_2:Exercise_5), I'd like to modify the test values to output the location of the match(es).

That is, the test value just gives "passed" if everything works all right. I modified line 127 to output "without match" if there was not a match (and this very simple mod works), but modifying line 142 to display the location/value of the match is not working. If I just use "leftstr[left]" as the value, I get weird values (L, ', etc.) and if I try to correct using say "(leftstr[left]-'0')" I also get weird values (Korean character, L, ?, etc.)

Ideally I would like to know how to cue up both the position and the value of the match(eS). FYI I am only at about K&R c. 2.9 and self-studying so the more you can use material from that (early) point forward, or a basic explanation of anything beyond that, the more I would appreciate your answers.

I copied the test driver with the modded lines tagged below. Thanks in advance.

/* test driver */

...

    for (left = 0; left < numlefts; left++)
    {
        for (right = 0; right < numrights; right++)
        {
            pos = any(leftstr[left], rightstr[right]);
            ptr = strpbrk(leftstr[left], rightstr[right]);

            if (-1 == pos)
            {
                if (ptr != NULL)
                {
                    printf("Test %d/%d failed.\n", left, right);
                    ++failed;
                }
                else
                {
                    printf("Test %d/%d passed, without match. \n", left, right); //mod
                    ++passed;
                }
            }
            else
            {
                if (ptr == NULL)
                {
                    printf("Test %d/%d failed.\n", left, right);
                    ++failed;
                }
                else
                {
                    if (ptr - leftstr[left] == pos)
                    {
                        printf("Test %d/%d passed, match at %c \n", left, right,
                                leftstr[left]);  //mod w/ issue
                        ++passed;
                    }
                    else
                    {
                        printf("Test %d/%d failed.\n", left, right);
                        ++failed;
                    }
                }
            }
        }
    }
    printf("\n\nTotal passes %d, fails %d, total tests %d\n", passed, failed,
            passed + failed);
    return 0;
}

Answer 1

If I just use "leftstr[left]" as the value, I get weird values

Of course you may get weird values when you try to print a char * (which leftstr[left] is, the whole string s1) with the conversion specifier c.

modifying line 142 to display the location/value of the match is not working.

                        printf("Test %d/%d passed, match at %c \n", left, right,
                                leftstr[left]);  //mod w/ issue

This is working:

            printf("Test %d/%d passed, match at position %d, value %c\n"
                , left, right, pos, *ptr);  //mod w/o issue