I am tring to remove three string from a que using nodes. When I try to remove the third one it does so, but then I get a debugging error. I think the problem is that I am not deleting the last node but I cannot figure out what I am doing wrong.
que1.add("Fish");
que1.add("Whale");
que1.add("Shark");
Que que3(que1);
que = que1;
cout<<que1.remove()<<endl;
cout<<que1.remove()<<endl;
cout<<que.remove()<<endl;
cout<<que.remove()<<endl;
cout<<que3.remove()<<endl;
cout<<que3.remove()<<endl;
cout<<que3.remove()<<endl; //this causes the run time error
if(!que1.isEmpty())//this causes the run time error
{
Que que4(que1);
cout<<que4.remove()<<endl;
cout<<que4.remove()<<endl;
}
else
{
cout<<"Is empty"<<endl;
}
return 0;
}here is the que.cpp file
Que::~Que()
{
Node * temp = front;
while (front)
{
temp = front->getLink();
delete front;
front = temp;
}
}
Que::Que()
{
front=NULL;
rear = NULL;
}
Que::Que(const Que &obj)
{
Node *walker;
Node *copy;
walker= obj.rear;
if(obj.isEmpty()){//check to see if node is null
front=NULL;
rear=NULL;
return;
}
copy=new Node(walker->getData(), NULL);//set to copy first node
rear =copy;
walker=walker->getLink();
while(walker) //if node not empty
{
copy->setLink(new Node(walker->getData(), NULL));//set values for new node
walker=walker->getLink(); //creates link
copy=copy->getLink();
}
front = copy; //set value to front
}
void Que::operator=(const Que & obj)
{
Node *walker;
Node *copy;
walker= obj.rear;
if(obj.isEmpty()){//check to see if node is null
front=NULL;
rear=NULL;
return;
}
copy=new Node(walker->getData(), NULL);//set to copy first node
rear =copy;
walker=walker->getLink();
while(walker)
{
copy->setLink(new Node(walker->getData(), NULL));
walker=walker->getLink();
copy=copy->getLink();
}
front = copy;
}
void Que::add(string file)
{
if(front==NULL && rear==NULL) //if node
{
front = new Node(file, NULL); //creates first node
rear=front;
}
else
{
front->setLink(new Node(file, NULL)); //sets link for node
front=front->getLink();
}
}
string Que::remove()
{
if(front==NULL && rear ==NULL) //nothing happens if empty
return "";
else if(front==rear && front!=NULL) //gets node if only one
{
string val = rear->getData();
delete rear;//deletes node
return val;
}
else //I am pretty sure this is what is causing the error
{
Node *temp;
temp=rear;
rear = rear->getLink();
string val = temp->getData();
delete temp;//deletes node
return val;
}
}
void Que::print()
{
printHelper(rear);
}
bool Que::isEmpty() const
{
if(!front)
return true;
else
return false;
}
void Que::printHelper(Node *temp)
{
if(!temp)
{
return;
}
else
{
printHelper(temp->getLink()); //sets to next node
cout<<temp->getData()<<endl;
}
}I don't think this is needed but I am including the header file
#ifndef QUEUE
#define QUEUE
#include "Node.h"
class Que
{
private:
Node* front;
Node *rear;
void printHelper(Node *);
public:
Que();
Que(const Que &);
~Que();
void add(string);
string remove();
bool isEmpty() const;
void operator=(const Que &);
void print();
};
#endif