Help with Refining the set_union function in C++

[hay_man]

Thanks all for your help. A true lifeline. However, as mentioned I need to implement a set class. I am mocking the STL Library set_union function in c++. Essentially,the intersection is performed on sets, not on strings. The set class ensures that each element is only stored once. Perhaps if this was written first then writing intersection is somewhat easier.
The set is stored in a vector which has the size() method therefore in the loop i need to replace vectore.length() with vector.size().

Thanks in advance.

// intersection of this set with another
// Pre: a StringSet object
// Post: returns a new StringSet which is the intersection 
//       of this  with otherset, ie. only the items common to both StringSets

StringSet StringSet::set_intersection(StringSet otherset)  //this line cannot change. I only want    to pass in 2 objects.

{
    // record chars that have already been found to intersect so that we don't
    // add them to result more than once
    int hits[256];
    //memset(hits, 0, sizeof(hits));
           
    string result;
    char cur;
    for ( int i = 0; i < contents.size(); i++) {
        cur = contents[i];
        // check if we already found char
        if (contents.find(cur) != string::npos) {
            if (hits[(int)cur] == 0) {
                // found new char
                hits[(int)cur] = 1;
                result += cur;
            } else {
                // already found char so don't add to result
            }
        }
    }

    return result;
}

[Daved]

What is the question?

[hay_man]

The function doesnt work as it stands. Can someone please assist me in fixing the errors inside it.
Ta, I

[Salem]

What doesn't work?
- doesn't compile?
- produces no answer?
- produces wrong answers?

Test it with some really simple sets, like "a" and "", "a" and "a", "a" and "b", "a" and "ab"
Step through the code with a debugger and observe what happens.