Thread: help me with some idea...

Originally Posted by laserlight

No. Here is an example of a wrapper:

Code:

class StringSet
{
public:
    // inserts value to contents
    void insert(const std::string& value)
    {
        contents_.insert(value);
    }

    // returns true if string set contents contains value
    bool contains(const std::string& value) const
    {
        return contents_.find(value) != contents_.end();
    }
private:
    std::set<std::string> contents_;
};

Of course, you would have your set_intersection(), set_union() and print() member functions implemented in terms of the std::set<std::string> member variable, possibly using the std::set_intersection() and std::set_union generic algorithms that I demonstrated in the other thread.

and also i need to #include <algorithm> in my stringset.h right?

how could i print those while compile?

Code:

// print
// Pre: None
// Post: the stringset will be printed to cout
void StringSet::print()
{
    for( int i=0; i<contents.size(); i++ ) 
        cout << "\t" << contents[i] << endl;
}

thank you very much " laserlight " ......

Originally Posted by laserlight

Yes, but since your sets are not ordered, you are looking at order n^2 performance.

so you mean i need to sort the contents first ????

The union of two sets is the set that contains all of the elements in the two sets. You can construct the union by first making an empty set and then inserting into it all elements from one set and then all elements from the other set.

>> am i right with this joni?
Not quite, you forgot to use otherset.

Originally Posted by Daved

>> am i right with this joni?
Not quite, you forgot to use otherset.

Code:

StringSet StringSet::set_union(StringSet otherset)
{
    StringSet UnionResult;
    
    for(int i = 0; i < contents.size(); i++)
    {
        UnionResult.insert( contents[i] );
        if( !UnionResult.contains( contents[i] ) && !otherset.contains( contents[i] ) )
            UnionResult.insert( contents[i] );
    }   
    return UnionResult;
}

is this cool?

You don't seem to be getting what the union of two sets really is...

The union contains all of the elements from both of the sets. Therefore the union is easily constructed by inserting all of the elements from both of the sets. For example if the two sets are {1,2,3,4} and {5,6,7}, their union is {1,2,3,4,5,6,7}.

Note that you already check for duplicates in the insert method so you don't need to worry about them now.

Originally Posted by joni

You don't seem to be getting what the union of two sets really is...

The union contains all of the elements from both of the sets. Therefore the union is easily constructed by inserting all of the elements from both of the sets. For example if the two sets are {1,2,3,4} and {5,6,7}, their union is {1,2,3,4,5,6,7}.

Note that you already check for duplicates in the insert method so you don't need to worry about them now.

first of all.. i need to thank you joni and daved.... really appreicated lot ...
so this is my final solution....

Code:

StringSet StringSet::set_union(StringSet otherset)
{
    StringSet UnionResult;
    
    for(int i = 0; i < contents.size(); i++)
    {
        UnionResult.insert( contents[i] );
        if( !UnionResult.contains( contents[i] ))
            UnionResult.insert( contents[i] );
            UnionResult.inser( otherset[i] );
    }   
    return UnionResult;
}

am i right with the code?