The if statment I am using in my main program is not working, it should return the else value, but is returning the information in the if part of the statment and then it causes a run time error. I am not sure what is going 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<<que.remove()<<endl;
cout<<que3.remove()<<endl;
cout<<que3.remove()<<endl;
cout<<que3.remove()<<endl;
if(!que1.isEmpty())//error happens here
{
Que que4(que1);
cout<<que4.remove()<<endl;
cout<<que4.remove()<<endl;
}
else
{
cout<<"Is empty"<<endl;
}here is the class file. I don't understand why isEmpty is not working.
Que::~Que()
{
/*Node * temp = rear;
while (rear)
{
temp = rear->getLink();
delete rear;
rear = 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
{
string val = front->getData();
Node *temp;
temp=rear;
while(temp->getLink()!=front)
temp=temp->getLink();
delete front;//deletes node
front =temp;
front->setLink(NULL);
return val;
}
}
void Que::print()
{
printHelper(rear);
}
bool Que::isEmpty() const//this should work, but it doesn't
{
if(!rear)
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;
}
}