DaniWeb Forum Index > Software Development > C++

C++ RSS

Using a class to add/delete/show numbers in a Link List

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Feb 2005

Posts: 4

Reputation: xsxixtxhx is an unknown quantity at this point

Solved Threads: 0

xsxixtxhx

Offline

Newbie Poster

Using a class to add/delete/show numbers in a Link List

Apr 2nd, 2005

I have this program that is supposed to take in numbers from the Main cpp file and add them to the link list. Eventually i have to sort them then display them on the screen. For right now i am just trying to insert them to the link list but i keep getting a complie error. I am trying to compile this program and i get the following error "'[HTML]Node' : no appropriate default constructor available[/HTML]" Any suggestions ?

I have attached a link to the files in case it is easier for you to view it that way
Project 3

Thanks

Here is my .h file which creates the file currently i am trying to get the Insert Fuction to work so i have the other set as commetns

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 //---------------------------------------------------------------------------
#ifndef RcrLnkListH
#define RcrLnkListH
//---------------------------------------------------------------------------
typedef int Item;
 
class List
{
public:
   List();// head(0) { }; 
   ~List();
 
   bool IsEmpty();
 
  void Show();
   bool Insert( Item item ); 
      //{ return Insert( head, item ); }
   //bool Delete( Item item );  
      //{ return Delete( head, item ); }*/
 
private:
   struct Node
   {
      Item item;
      Node *next;
 
      Node( Item itm, Node * nxt ) 
		  : item(itm), next(nxt) { }
   };
 
   Node * head;
 
   void Show( Node * node );
   bool Insert( Node * &node, Item item );
   /*bool Delete( Node * & node, Item item );*/
};
//---------------------------------------------------------------------------
#endif
 //---------------------------------------------------------------------------
#ifndef RcrLnkListH
#define RcrLnkListH
//---------------------------------------------------------------------------
typedef int Item;

class List
{
public:
   List();// head(0) { }; 
   ~List();

   bool IsEmpty();

  void Show();
   bool Insert( Item item ); 
      //{ return Insert( head, item ); }
   //bool Delete( Item item );  
      //{ return Delete( head, item ); }*/

private:
   struct Node
   {
      Item item;
      Node *next;

      Node( Item itm, Node * nxt ) 
		  : item(itm), next(nxt) { }
   };

   Node * head;

   void Show( Node * node );
   bool Insert( Node * &node, Item item );
   /*bool Delete( Node * & node, Item item );*/
};
//---------------------------------------------------------------------------
#endif

Here is my implemtation file which define the functions in the class:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <iomanip>
#include <cstdlib>
#pragma hdrstop
#include "RcrLnkListH.h"
using namespace std;
 
 
List:: List(): head(0) { }; 
 
 
 
List:: ~List()
{
}
 
 
bool List:: IsEmpty()
{
	return head ==0;
}
 
 
void List:: Show()
{
void Show( Node * node );
 
}
 
 
void List::Show(Node *node)
{
if (node != NULL)
		cout<<node->item;
		Show(node->next);
 
}
 
bool List:: Insert( Item item ) 
      { 
 
		bool Insert( Node * &node, Item item );
		return Insert( head, item ); }
 
 
bool List:: Insert( Node * &node, Item item ) 
{
	if ((node == NULL) || (item < node->item))
	{
 
		Node *newPtr = new Node ;
		if (newPtr == NULL)
		{}
		else
		{
			newPtr->item = item;
			newPtr->next = node;
			node = newPtr;
		}
	}
	else Insert(node->next, item);
return Insert( head, item );
}
 
/*bool Delete(Node * & node, Item item)  
      { return Delete( head, item ); }*/
#include <iostream>
#include <iomanip>
#include <cstdlib>
#pragma hdrstop
#include "RcrLnkListH.h"
using namespace std;


List:: List(): head(0) { }; 


   
List:: ~List()
{
}


bool List:: IsEmpty()
{
	return head ==0;
}
   

void List:: Show()
{
void Show( Node * node );

}


void List::Show(Node *node)
{
if (node != NULL)
		cout<<node->item;
		Show(node->next);

}

bool List:: Insert( Item item ) 
      { 
		
		bool Insert( Node * &node, Item item );
		return Insert( head, item ); }

	  
bool List:: Insert( Node * &node, Item item ) 
{
	if ((node == NULL) || (item < node->item))
	{
		
		Node *newPtr = new Node ;
		if (newPtr == NULL)
		{}
		else
		{
			newPtr->item = item;
			newPtr->next = node;
			node = newPtr;
		}
	}
	else Insert(node->next, item);
return Insert( head, item );
}
   
/*bool Delete(Node * & node, Item item)  
      { return Delete( head, item ); }*/

Finally here is my Main CPP file

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
//---------------------------------------------------------------------------
#include <iostream>
#pragma hdrstop
#include "RcrLnkListH.h"
using namespace std;
//---------------------------------------------------------------------------
 
int main(int argc, char* argv[])
{
   List list;
 
   if (list.IsEmpty == 0)
   {
	   cout<<"not";
   }
   else 
	   cout<<"is empty";
   list.Show();
 
   list.Insert(3);
   //list.Insert(1);
   //list.Insert(2);
   //list.Insert(5);
  // list.Insert(4);
 
   list.Show();
 
  // list.Delete(3);   list.Show();
  // list.Delete(1);   list.Show();
  // list.Delete(5);   list.Show();*/
 
   cin.get();
   return 0;
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
#include <iostream>
#pragma hdrstop
#include "RcrLnkListH.h"
using namespace std;
//---------------------------------------------------------------------------

int main(int argc, char* argv[])
{
   List list;

   if (list.IsEmpty == 0)
   {
	   cout<<"not";
   }
   else 
	   cout<<"is empty";
   list.Show();

   list.Insert(3);
   //list.Insert(1);
   //list.Insert(2);
   //list.Insert(5);
  // list.Insert(4);

   list.Show();

  // list.Delete(3);   list.Show();
  // list.Delete(1);   list.Show();
  // list.Delete(5);   list.Show();*/

   cin.get();
   return 0;
}
//---------------------------------------------------------------------------

•

Join Date: Sep 2004

Posts: 7,566

Reputation: Narue has a reputation beyond repute

Solved Threads: 705

Narue

Offline

Code Goddess

Re: Using a class to add/delete/show numbers in a Link List

Apr 2nd, 2005

>Node *newPtr = new Node ;
You're trying to use a constructor with no arguments, yet your Node is declared as:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
struct Node
{
   Item item;
   Node *next;
 
   Node( Item itm, Node * nxt ) 
	: item(itm), next(nxt) { }
};
struct Node
{
   Item item;
   Node *next;

   Node( Item itm, Node * nxt ) 
	: item(itm), next(nxt) { }
};

Notice how the only constructor declared takes two arguments. If you declare any constructors then the default constructor is not created automagically for you.

>Any suggestions ?
Be prepared for a good time trying to get this program to work. :mrgreen:

I'm here to prove you wrong.

•

Join Date: Feb 2005

Posts: 4

Reputation: xsxixtxhx is an unknown quantity at this point

Solved Threads: 0

xsxixtxhx

Offline

Newbie Poster

Re: Using a class to add/delete/show numbers in a Link List

Apr 2nd, 2005

does anyone have any hits on how i can redo the implemenation of Insert to get this to work ?

Thanks

•

Join Date: Sep 2004

Posts: 7,566

Reputation: Narue has a reputation beyond repute

Solved Threads: 705

Narue

Offline

Code Goddess

Re: Using a class to add/delete/show numbers in a Link List

Apr 2nd, 2005

>does anyone have any hits on how i can redo the implemenation of Insert to get this to work ?
Don't use recursion. Not only does it complicate a simple algorithm, it's potentially dangerous for long lists. I generally prefer to avoid recursion for linear data structures. If you can't efficiently divide the structure in half then that's an indication that recursion may not be the best solution.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <cstdlib>
#include <iostream>
 
using namespace std;
 
struct node {
  int data;
  node *next;
 
  node ( int init, node *link )
    : data ( init ), next ( link )
  {}
};
 
node *insert ( node *list, int data )
{
  if ( list == 0 ) {                // Empty list
    list = new node ( data, 0 );
  } else if ( data < list->data ) { // New head
    list = new node ( data, list );
  } else {                          // Everywhere else
    node *it = list;
 
    while ( it->next != 0 && data > it->next->data )
      it = it->next;
 
    it->next = new node ( data, it->next );
  }
 
  return list;
}
 
void print ( node *list )
{
  while ( list != 0 ) {
    cout<< list->data <<' ';
    list = list->next;
  }
 
  cout<<endl;
}
 
int main()
{
  node *list = 0;
 
  for ( int i = 0; i < 10; i++ )
    list = insert ( list, rand() % 100 );
 
  print ( list );
}
#include <cstdlib>
#include <iostream>

using namespace std;

struct node {
  int data;
  node *next;

  node ( int init, node *link )
    : data ( init ), next ( link )
  {}
};

node *insert ( node *list, int data )
{
  if ( list == 0 ) {                // Empty list
    list = new node ( data, 0 );
  } else if ( data < list->data ) { // New head
    list = new node ( data, list );
  } else {                          // Everywhere else
    node *it = list;

    while ( it->next != 0 && data > it->next->data )
      it = it->next;

    it->next = new node ( data, it->next );
  }

  return list;
}

void print ( node *list )
{
  while ( list != 0 ) {
    cout<< list->data <<' ';
    list = list->next;
  }

  cout<<endl;
}

int main()
{
  node *list = 0;

  for ( int i = 0; i < 10; i++ )
    list = insert ( list, rand() % 100 );

  print ( list );
}