help me with some idea...

hi everyone ... i am doing the intersection, can someone let me know which intersect with which please... as i am really confuse on the StringSet otherset .. here is my code and class...

which is on red color..

this is my implementation code

Code:

---


#include "stringset.h"

// insert a value into the set
// Pre: a string value
// Post: the value is inserted into the set if it
//      is not already present
void StringSet::insert(string value)
{
    if( !contains(value) )
    {
        contents.push_back(value);
    }
}   

// test for a value
// Pre: a string value
// Post: returns 1 if the value is present in the StringSet, 0 otherwise
int StringSet::contains(string value)
{
    int loc;
    bool found = false;
   
    for(loc = 0; loc < contents.size(); loc++)
        if(contents[loc] == value)
        {
              found = true;
              break;
        }
    if(found)
        return 1;
    else
        return 0;
 
}
// 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)
{
         

}

// union of this set with another
// Pre: a StringSet object
// Post: returns a new StringSet which is the union
//      of this  with otherset, ie. the items in either StringSets
StringSet StringSet::set_union(StringSet otherset)
{
 
}


// 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;
}

---

and this is my mainc.pp

Code:

---


#include "inverted_index.h"

int main()
{

  StringSet ss;

  ss.insert("one");
  ss.insert("two");
  ss.insert("three");
  ss.insert("one");
 

  ss.print();
  if ( ss.contains("one") )
    cout << "ok - contains('one')\n";
  else
    cout << "fail - contains('one')\n";
/* 
  // test the InvertedIndex
 InvertedIndex idx;
 idx.tally("cat", "cats.txt");
 idx.tally("cat", "animals.txt");
 idx.tally("cat", "everything.txt");
 idx.tally("dog", "dogs.txt");
 
 idx.print();
  // searching idx for cat should give us three files
  vector <string> query;
  query.push_back("cat");
  StringSet si = idx.search(query);
  if (si.contains("cats.txt") && si.contains("animals.txt") && si.contains("everything.txt") )
    cout << "ok - search('cat')\n";
  else
    cout << "fail - search('cat')\n";

  if (si.contains("dogs.txt"))
    cout << "fail - search('cat') -- dogs.txt found\n";
  else
    cout << "ok - search('cat') no dogs\n";

*/
  system("PAUSE");
  return 0;
}

---

this is another implementation which might be helpful ...

Code:

---


#include "inverted_index.h"
#include "osdir.h"



// InvertedIndex::tally
//  Pre: a word and file pair as strings
//  Post: adds the file to the index under word
 void InvertedIndex::tally(string word, string file)
{
      storage.push_back(word);
      //storage.push_back(file);
     
      //vector<string>::iterator theIterator = storage.end();
      //storage.insert( theIterator, file );
}

// InvertedIndex::search
// Pre: a vector of strings as search terms
// Post: a vector of strings being the files that all of the
//      input words occur in in the index.
StringSet InvertedIndex::search(vector <string> words)
{

}

// print
// Pre: an index structure
// Post: renders the index on the screen
void InvertedIndex::print()
{
    for(int i = 0; i < storage.size(); i++)
    {
        cout<<endl<<storage[i]<<" ";
    }
    cout<<endl<<endl;
}

//
// These  methods have been written for you, there is no need to change
// anything below this text.  These methods make use of the other
// methods defined above.
//


// IndexFile
//  Pre: a file name as a string
//  Post: the words in the file are added to the inverted index
void InvertedIndex::indexFile( string filename ) {

        vector <string> words = ReadFile(filename);
        for(int i=0; i<words.size(); i++) {
                tally(words[i], filename);
        }
}

void InvertedIndex::indexDir( string dirname ) {

  string filename;
  oslink::directory dir(dirname);
  while (dir) {
    filename = dirname + "/" + dir.next();
    indexFile(filename);
  }
}

---

The intersection of two sets is the set that contains the elements that are present in both of the two sets. That is, if c is an element in "this" set, then c is in the intersection if and only if otherset.contains(c). So a very basic algorithm could create an empty set to hold the intersection, go through the elements in one of the sets and check if they are in the other one too, and if they are, add them to the intersection set.

can you provide some sample as i am relly newbie on this ... thank you .. and will really appreciated..

i am trying to do it, this is my code.. but please correct for me ..
(anyone)

Code:

---


StringSet StringSet::set_intersection(StringSet otherset)
{
    stringset result;

    for(int i = 0; i < contents.size(); i++)
        if(otherset.contains(contents[i])
            result = contents[i]; 
}

---

> result = contents[i];

Instead of setting result to contents[i], you want to insert contents[i] to the result. So something like

Code:

---

result.insert(contents[i]);

---

will this work??

Code:

---


StringSet StringSet::set_intersection(StringSet otherset)
{
    stringset result;

    for(int i = 0; i < contents.size(); i++)
        if(otherset.contains(contents[i])
            result.insert(contents[i]);
}

---

Have you tried it?

Is your class called stringset or StringSet? You use both.

The function is declared to return StringSet but you don't have a "return" statement.

peter_hii, is this homework? If it is not, then you really might want to use what I suggested in your other thread.

Quote:

---

Originally Posted by joni

Have you tried it?

Is your class called stringset or StringSet? You use both.

The function is declared to return StringSet but you don't have a "return" statement.

---

it is StringSet...

Code:

---


StringSet StringSet::set_intersection(StringSet otherset)
{
    StringSet result;

    for(int i = 0; i < contents.size(); i++)
        if(otherset.contains(contents[i])
            result.insert(contents[i]);
}

---

got error

L:\assignment 2\stringset.cpp In member function `StringSet StringSet::set_intersection(StringSet)':
56 L:\assignment 2\stringset.cpp expected `)' before "result"
L:\assignment 2\Makefile.win [Build Error] [stringset.o] Error 1

Quote:

---

Originally Posted by laserlight

peter_hii, is this homework? If it is not, then you really might want to use what I suggested in your other thread.

---

the format is unchangeble.. but really appreciate that you done that.. really make sense for me ...
and using set is really easy but i want to stick with my own format......

Quote:

---

the format is unchangeble.. but really appreciate that you done that.. really make sense for me ...
and using set is really easy but i want to stick with my own format......

---

If that is the case, then use your StringSet class as a wrapper class for std::set<std::string>, instead of making it a typedef.

Quote:

---

Originally Posted by peter_hii

L:\assignment 2\stringset.cpp In member function `StringSet StringSet::set_intersection(StringSet)':
56 L:\assignment 2\stringset.cpp expected `)' before "result"
L:\assignment 2\Makefile.win [Build Error] [stringset.o] Error 1

---

Well, like it says, the compiler is expecting to find a ")" before the word "result" on line 56. It doesn't get plainer than that. You are missing a closing parenthesis.

Quote:

---

Originally Posted by laserlight

If that is the case, then use your StringSet class as a wrapper class for std::set<std::string>, instead of making it a typedef.

---

you mean ??

for the declaration// make it set<string> stringset; ???

Quote:

---

Originally Posted by joni

Well, like it says, the compiler is expecting to find a ")" before the word "result" on line 56. It doesn't get plainer than that. You are missing a closing parenthesis.

---

yap as what you said and machine error.... i miss one " )" .. very appreciated... i am trying on the code now ....

Quote:

---

for the declaration// make it set<string> stringset; ???

---

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.

Quote:

---

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;
}

---

Quote:

---

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

---

You only need to #include <set> and <string> in stringset.h
You should #include <algorithm> in stringset.cpp

The reason being that std::set_intersection and std::set_union never need to be visible to the user of the StringSet class, but std::set and std::string need to be in the class definition (to declare the member variable).

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

Quote:

---

Originally Posted by joni

Have you tried it?

Is your class called stringset or StringSet? You use both.

The function is declared to return StringSet but you don't have a "return" statement.

---

hi Joni,

is this the correct way ??

Code:

---

StringSet StringSet::set_intersection(StringSet otherset)
{
    StringSet result;

    for(int i = 0; i < contents.size(); i++)
    {
        if(otherset.contains(contents[i]))
            result.insert(contents[i]);
    } 
    return result; 
}

---

and can someone or JONI please correct my union code...

Code:

---


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

---

Quote:

---

is this the correct way ??

---

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

Quote:

---

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 ????

Quote:

---

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

---

It is not needed, but it may be more efficient. If you make your class a wrapper of std::set<std::string> as I suggested, then you get this optimisation for free since std::set keeps its elements in sorted order.

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.

Quote:

---

Originally Posted by joni

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.

---

instead of storing them in the result...i need to create a new set right??

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] );
    } 
    return UnionResult;
}

---

am i right with this joni?

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

Quote:

---

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.

Quote:

---

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?

That does not look right. What I suggest is that you copy over the contents of one set to the result set (no need to check for duplicates, hence no need to use insert), and then use the insert member function to insert the contents of the other set into the result set.

what you mean by this ?? ?? :) cheers

as i know that otherset is a StringSet... it can't used of insert


i try this

Code:

---


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

---

i being thinking .......

insert otherset into contents
and another loop to insert the overall contents into UnionResult....is tat alright?

Code:

---


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

---

More like:

Code:

---

StringSet StringSet::set_union(const StringSet& otherset) const
{
    StringSet result;

    // copy over contents of this StringSet
    result.contents.assign(contents.begin(), contents.end());

    // insert the contents of the other StringSet
    for (unsigned int i = 0; i < otherset.contents.size(); ++i)
    {
        result.insert(otherset.contents[i]);
    }

    return result;
}

---

is the assign keywords?
new for me .. hehe....can you please explain...? thank you ...

I am assuming that the contents member variable is a standard container such as a std::vector. You should read up on what assign() does.

ok i understand assign() by viewing www.cppreference.com
really thanx laserlight .. you are brilliant...

one more question which i dont really understand why i could not display wat i want....

this is my class = header file

Code:

---



#include <string>
#include <iostream>
#include <vector>
#include "stringset.h"

using namespace std;


class InvertedIndex
{
//insert data member here
  struct inputType
  {
      string word;
      StringSet file;
  };
 
  vector<inputType> list;

public:
 
  // Tally adds one word/file pair to the index
  void tally(string word, string file);

---

and this is my implementation code

Code:

---


#include "inverted_index.h"
#include "osdir.h"

// InvertedIndex::tally
//  Pre: a word and file pair as strings
//  Post: adds the file to the index under word
void InvertedIndex::tally(string word, string file)
{
    inputType input;

    list.push_back( input );
}

// print
// Pre: an index structure
// Post: renders the index on the screen
void InvertedIndex::print()
{
    for( vector<inputType>::const_iterator output = list.begin(); output != list.end(); output++ )
    cout << "Word: " << output->word << "\t\tFile: " << output->file << endl;
}

---

and the main code

Code:

---


#include "inverted_index.h"

int main()
{
 
  // test the InvertedIndex
 InvertedIndex idx;
 idx.tally("cat", "cats.txt");
 idx.tally("cat", "animals.txt");
 idx.tally("cat", "everything.txt");
 idx.tally("dog", "dogs.txt");
 idx.print();

---

why the output is empty. ??

can someone please help on this serioes problem of mine????anyone?