Set Class - Insert Function

Please support our C++ advertiser: Programming Forums - DaniWeb Sister Site
Reply

•
•
Join Date: Mar 2009
Posts: 11
Reputation: boydale1 is an unknown quantity at this point 
Solved Threads: 0
boydale1 boydale1 is offline Offline
Newbie Poster

Set Class - Insert Function

 
0
  #1
Apr 13th, 2009
I am working on a set class and I have successfully written an insert function, but I need the function to insert in an ordered fashion.

C++ Syntax (Toggle Plain Text) 
  1. bool Set::insert( const EType & A )
  2. {
  3.    bool Flag = false;
  4.    unsigned Position = 0;
  5.    Node * Prev = Head;
  6.    Node * Curr = Head->Succ;
  7.    Node * Temp;
  8.  
  9.    Temp = new Node;
  10.    if (Temp != NULL )
  11.    {
  12.       Temp->Item = A;
  13.       Temp->Succ = Curr;
  14.       Prev->Succ = Temp;
  15.       Num++;
  16.       Flag = true;
  17.    }
  18.    return Flag;
  19. }

C++ Syntax (Toggle Plain Text) 
  1. Set::Set()
  2. {
  3.    Num = 0;
  4.    Head = new (nothrow) Node;
  5.    Head->Succ = NULL;
  6. }

C++ Syntax (Toggle Plain Text) 
  1. class Set
  2. {
  3.   private:
  4.  
  5.     struct Node
  6.     {
  7.       EType Item;     // User data item
  8.       Node * Succ;    // Link to the node's successor
  9.     };
  10.  
  11.     unsigned Num;     // Number of user data items in the set
  12.     Node * Head;      // Link to the head of the chain

Tell me if anything else is needed
Reply With Quote Quick reply to this message  
•
•
Join Date: May 2008
Posts: 376
Reputation: Clockowl is on a distinguished road 
Solved Threads: 27
Clockowl's Avatar
Clockowl Clockowl is offline Offline
Posting Whiz

Re: Set Class - Insert Function

 
0
  #2
Apr 13th, 2009
Scan the set until you find a value higher or lower (depends on how you sort) then the current value, insert it there?
Reply With Quote Quick reply to this message  
•
•
Join Date: Mar 2009
Posts: 11
Reputation: boydale1 is an unknown quantity at this point 
Solved Threads: 0
boydale1 boydale1 is offline Offline
Newbie Poster

Re: Set Class - Insert Function

 
0
  #3
Apr 13th, 2009
I tried doing that several separate times, but i cannot avoid a segmentation fault.

C++ Syntax (Toggle Plain Text) 
  1. bool Set::insert( const EType & A )
  2. {
  3.    bool Flag = false;
  4.    unsigned Position = 0;
  5.    Node * Prev = Head;
  6.    Node * Curr = Head->Succ;
  7.  
  8.    while ( (Curr->Item < A) and (Curr->Succ != NULL) )
  9.    {
  10.       Prev = Curr;
  11.       Curr = Curr->Succ;
  12.       cout << Curr->Item;
  13.    }
  14.  
  15.    if ( (Curr->Item != A) or (Curr == NULL) )
  16.    {
  17.       Node * Temp;
  18.       Temp = new Node;
  19.  
  20.       Temp->Item = A;
  21.       Temp->Succ = Curr;
  22.       Prev->Succ = Temp;
  23.       Num++;
  24.       Flag = true;
  25.    }
  26.    return Flag;
  27. }
Reply With Quote Quick reply to this message  
•
•
Join Date: May 2008
Posts: 376
Reputation: Clockowl is on a distinguished road 
Solved Threads: 27
Clockowl's Avatar
Clockowl Clockowl is offline Offline
Posting Whiz

Re: Set Class - Insert Function

 
0
  #4
Apr 13th, 2009
cpp Syntax (Toggle Plain Text) 
  1.    while ( (Curr->Item < A) and (Curr->Succ != NULL) )
  2.    {
  3.       Prev = Curr;
  4.       Curr = Curr->Succ;
  5.       cout << Curr->Item;
  6.    }

That code sets Curr to the last item in the set that's smaller than A.
And then you compare the last item (curr->item) to A (to guarantee uniqueness) or NULL for the last item. And there's your problem I think, hehe.

What if Curr is NULL and you try to dereference Curr->item? Segfault. I hope that's the error.

So, correct code would be something like..

cpp Syntax (Toggle Plain Text) 
  1. if(Curr == NULL){
  2. //create new item, append it to the set
  3. } else if (Curr->Item != A) {
  4. //create new item, insert it between the two items.
  5. }
Last edited by Clockowl; Apr 13th, 2009 at 2:44 pm.
Reply With Quote Quick reply to this message  
•
•
Join Date: Mar 2009
Posts: 11
Reputation: boydale1 is an unknown quantity at this point 
Solved Threads: 0
boydale1 boydale1 is offline Offline
Newbie Poster

Re: Set Class - Insert Function

 
0
  #5
Apr 13th, 2009
I don't really understand the last post. I do understand the second part, but I'm confused about the while loop still.
Reply With Quote Quick reply to this message  
•
•
Join Date: May 2008
Posts: 376
Reputation: Clockowl is on a distinguished road 
Solved Threads: 27
Clockowl's Avatar
Clockowl Clockowl is offline Offline
Posting Whiz

Re: Set Class - Insert Function

 
0
  #6
Apr 13th, 2009
While the current node's item is smaller than A and the current item isn't NULL (and thus we are at the end of the list), go to the next node.
Reply With Quote Quick reply to this message  
Reply

Quick Reply to Thread
This thread is more than three months old.
Perhaps start a new thread instead?
•
•
•
•
•
•
•
•
Message:
•
•
•
•



Similar Threads
Other Threads in the C++ Forum


Views: 612 | Replies: 5
Thread Tools Search this Thread



Tag cloud for C++
6 add api array arrays assignment beginner binary bitmap c++ c/c++ calculator char class classes code compile compiler console conversion convert count data delete desktop directshow dll encryption error file forms fstream function functions game getline givemetehcodez google graph homeworkhelper iamthwee ifstream input int integer java lazy lib linkedlist linux loop looping loops map math matrix memory multidimensional newbie news node number output parameter pointer problem program programming project proxy python random read recursion recursive reference return sort string strings struct studio system template templates text tree unix url variable vector video visual visualstudio win32 windows winsock word wordfrequency wxwidgets
About Us | Contact Us | Advertise | DaniWeb | Acceptable Use Policy | RSS Feed

©2003 - 2009 DaniWeb® LLC