Help with finding the intersection of 2 strings

Hi,
I'm just about done with implemting code for procurring the intersection of 2 strings and returns a 3rd string that is the intersection. However, i have some errors occuring, refer to the code below.
Any help would be appreciated,
thanks,
I

Code:

StringSet StringSet::set_intersection(set1 set2)
{
    // 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]; //ERROR OCCURS HERE cannot convert `std::basic_string<char, std::char_traits<char>, std::allocator<char> >' to `char' in assignment 
       

        if (contents.find(cur) != string::npos)//ERROR OCCURS HERE, CANNOT USE "FIND FUNCTION" {
            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; //ERROR conversion from `std::string' to non-scalar type `StringSet' requested 
}

>cur = contents[i]; //ERROR
Presumably, contents is an array or vector of strings. You can't assign a string to a char.

>if (contents.find(cur) != string::npos)//ERROR
Perhaps you meant:

Code:

if (contents[i].find(cur) != string::npos)

>return result; //ERROR
result is defined as a string but your function returns a StringSet. If you're getting an error, the two types are not compatible.

how do i then go about returning a StringSet?
ta,
I

>how do i then go about returning a StringSet?
Maybe change result to a StringSet and use the interface you've defined to fill it with whatever your results are? I really have no idea how to use a StringSet since it appears that you're the one defining it, and you haven't shown us the definition.

Here's my stringset.h header file:

Code:

#include <vector>
#include <string>
#include <iostream>

using namespace std;

class StringSet 
{
private: 

vector <string> contents;
 
public:

void insert(string value);
  
int contains(string value); 
  
StringSet set_intersection(StringSet otherset);
  
StringSet set_union(StringSet otherset);          
  
  
void print();
  
};

>Here's my stringset.h header file:
Um, we're not going to tell you how to use a class that you write yourself. If you wrote it then you should have no problem using it. If you do have a problem, then you have more of a problem than returning a StringSet.