I have to make a copy constructor for a queue class and decided to use enqueue to put the files in, but for some reason it gives a runtime error. so I really need some help in figuring out what is wrong. Thanks in advanced
#include <cstddef>
#include <string>
#include <cstdlib>
#include <iostream>
#include "cpqueue.h"
using namespace std;
CpQueue::CpQueue()
{
first = NULL;
last = NULL;
} // end default constructor
//copy constructor
CpQueue::CpQueue(const CpQueue& source)
{
if(!source.isEmpty())
{
Node *orig = source.first;
char newItem;
do
{
newItem = orig->item;
cout << newItem
<< "\n";
enqueue(newItem);//giving runtime error
//cout << "your passed here\n";
orig = orig->next;
}while(orig != source.first);
}
else
{
cout << "\nError in copy\n";
exit(1);
}
}// end copy constructor
//destructor
CpQueue::~CpQueue()
{
while(!isEmpty())
{
dequeue();
}
first = NULL;
last = NULL;
}//end destructor
//methods
// check empty
bool CpQueue::isEmpty() const
{
return last == NULL;
}// end isempty
//add to queue
void CpQueue::enqueue(char newItem)
{
//create node
Node *newPtr = new Node;
//set data
newPtr->item = newItem;
newPtr->next = NULL;
newPtr->prev = NULL;
//insert new Node
if(isEmpty())
{
first = newPtr;
}
else
{
last->next = newPtr;
newPtr->prev = last;
}
//new node is always at back
last = newPtr;
}
// remove from queue
char CpQueue::dequeue()
{
char data;
if(isEmpty())
{
cout << "\nError empty Queue.\n";
exit(1);
}
else // queue not empty
{
data = first->item;
Node *temp = first;
//only one node
if(first == last)
{
first = NULL;
last = NULL;
}
//more nodes
else
{
first = first->next;
first->prev = last;//or NULL not circle
}
temp->next = NULL;
temp->prev = NULL;
delete temp;
return data;
}//end else
}//end dequeue
//view first
char CpQueue::getFront() const
{
if(isEmpty())
{
cout << "\n Error queue empty \n";
exit(1);
}
else
{
return first->item;
}
}// end getFront
//overrides
CpQueue CpQueue::operator= (const CpQueue& source)
{
return CpQueue(source);
}
bool CpQueue::operator== (const CpQueue& source)
{
}
