Car Wash Queue Issue - c++

Question

I'm working on a variation of the "Car Queue" or "Car Wash" problem in which I have to input how long a car will take to wash, the odds of a car entering the queue for the wash at any given moment, and then receive as output how many cars were washed, how many cars were left in the queue at the end of the day, and how much total waiting time there was. I'm still very new to c++, and have only been using it extensively for the last few months. Its very possible there's an error with my queue implementation code that I didn't catch, but I believe the error is in the main. Currently, I added outputs for every loop, so I could watch the code run, and follow it. It appeared to be accepting a car, and then immediately finishing the wash on it. Then, when no car is present, it simply alternates between a washing and waiting loop. Any help would be greatly appreciated.
#include <assert>
#include <iostream>
#include <fstream>
#include <ostream>
#include <ctime>
#include <cstdlib>
using namespace std;
class Node
{
private:
int item;
Node * next;
public:
Node ();
Node (const int& anItem);
Node (const int& anItem, Node * nextNodePtr);
void setItem (const int& anItem);
void setNext (Node * nextNodePtr);
int getItem ();
Node* getNext();
};
class LinkedQueue
{
private:
Node* backPtr;
Node* frontPtr;
public:
bool isEmpty();
bool enqueue(int& newEntry);
bool dequeue();
int peekFront() const;
LinkedQueue();
~LinkedQueue();
LinkedQueue(const LinkedQueue& aQueue);
};
int main ()
{
srand(1);
int timeForWash;
int minute;
int timeEnteredQueue;
int carsWashed;
int totalQueueMin;
int timeLeftOnCar;
int probOfArrival;
int carsInQueue = 0;
LinkedQueue carQueue;
cout << "Enter time to wash one car:" << endl;
cin >> timeForWash;
cout << endl;
cout << "Enter probability of arrival per minute" << endl;
cin >> probOfArrival;
carsWashed = 0;
totalQueueMin = 0;
timeLeftOnCar = 0;
for (minute = 1; minute <= 20; ++minute)
{
if (rand()%100 <= probOfArrival)
{
carQueue.enqueue(minute);
carsInQueue++;
cout << "Queued" << endl;
}
if ((timeLeftOnCar == 0) && ( !carQueue.isEmpty()))
{
timeEnteredQueue = carQueue.peekFront();
carQueue.dequeue();
totalQueueMin = totalQueueMin + (minute - timeEnteredQueue);
++carsWashed;
carsInQueue--;
timeLeftOnCar = timeForWash;
cout << "Finish" << endl;
}
if (timeLeftOnCar =! 0)
{
timeLeftOnCar -= 1;
cout << "Washing" << endl;
}
if ((timeLeftOnCar == 0) && ( carQueue.isEmpty()))
{
cout << "Waiting" << endl;
}
}
cout << carsWashed << endl;
cout << totalQueueMin << endl;
cout << carsInQueue << endl;
system("pause");
return(0);
};
//Implementation
Node:: Node() : next (nullptr)
{
} // default
Node:: Node (const int& anItem) : item(anItem), next(nullptr)
{
}
Node:: Node (const int& anItem, Node * nextNodePtr) : item(anItem), next(nextNodePtr)
{
}
void Node:: setItem (const int& anItem)
{
item = anItem;
}
void Node:: setNext (Node * nextNodePtr)
{
next = nextNodePtr;
}
int Node:: getItem ()
{
return item;
}
Node * Node:: getNext ()
{
return next;
}
bool LinkedQueue::enqueue(int& newEntry)
{
Node* newNodePtr = new Node(newEntry);
//Insert the new node
if (isEmpty())
frontPtr = newNodePtr; // The queue was empty
else
backPtr->setNext(newNodePtr); // The queue was not empty
backPtr = newNodePtr; // New node is at back
return true;
} // end enqueue
bool LinkedQueue::dequeue()
{
bool result = false;
if (!isEmpty())
{
// Queue is not empty; remove front
Node* nodeToDeletePtr = frontPtr;
if (frontPtr == backPtr)
{ // Special case: one node in queue
frontPtr = nullptr;
backPtr = nullptr;
}
else
frontPtr = frontPtr->getNext();
// Return deleted node to system
nodeToDeletePtr->setNext( nullptr);
delete nodeToDeletePtr;
nodeToDeletePtr = nullptr;
result = true;
} // end if
return result;
} // end dequeue
bool LinkedQueue:: isEmpty()
{
return (frontPtr == nullptr );
}
int LinkedQueue:: peekFront() const
{
return frontPtr->getItem();
}
LinkedQueue::LinkedQueue()
{
frontPtr = nullptr;
backPtr = nullptr;
}
LinkedQueue::LinkedQueue( const LinkedQueue& aQueue) :
frontPtr(aQueue.frontPtr)
{
} // end copy constructor
LinkedQueue::~LinkedQueue()
{
} // end destructor

Answer 1

timeLeftOnCar =! 0 is the same as timeLeftOnCar = !0, which is timeLeftOnCar = 1, which is always true.
You wanttimeLeftOnCar != 0 or timeLeftOnCar > 0.