finding the minimum value in circular array queue

public class CanadaTour {
private CircularArrayQueue<City> cityQueue;
private Map map;
private City startCity;
public CanadaTour (String fileName) {
map = new Map();
cityQueue = new CircularArrayQueue<City>();
loadData(fileName);
}
private void loadData (String file) {
MyFileReader reader = new MyFileReader(file);
reader.readString(); // First line of headers.
String cityName = null;
int locX = 0;
int locY = 0;
double earnings = 0;
int cityID = 0;
while (!reader.endOfFile()) {
cityName = reader.readString();
locX = reader.readInt();
locY = reader.readInt();
earnings = reader.readDouble();
cityID ++;
City city = new City(cityID, cityName, locX, locY, earnings);
if (cityID == 1) {
startCity = city;
}
cityQueue.enqueue(city);
map.addCity(city);
}
}
public City findNextCity (City currCity, double currMoney) {
double distance = 0;
City result = cityQueue.dequeue();
if (result != currCity || result.isMarkedInStack() 
|| result.isMarkedOutOfStack())  //add other conditionals
distance = distBetweenCities(result, currCity);
cityQueue.enqueue(result);
double distance1;	
for (int i = 1; i < cityQueue.getLength(); i ++) {
City result1 = cityQueue.dequeue();
if (result1 != currCity || result1.isMarkedInStack() 
|| result1.isMarkedOutOfStack()) { //add other conditionals
distance1 = distBetweenCities(result1, currCity);
if (distance1 < distance) {
distance = distance1;
return result1;
}
cityQueue.enqueue(result1);
}
}
return result;		
}
public double distBetweenCities (City city1, City city2) {
double result =  Math.sqrt(Math.pow(city2.getX() - city1.getX(), 2) + 
Math.pow(city2.getY() - city2.getY(), 2) * 1.0);
return result;
}
public double calcFlightCost (double distance) {
double flightCost;
if (distance < 100.0) {
flightCost = 127.00;
} else {
flightCost = (1.25 * distance) + 32.0;
}
return flightCost;
}

This is what I have thus far, but logically my answer seems wrong for the findNextCity method. and additionally, I don't even know how to approach the second part of the question (below).

I am supposed to go through each element in the cityQueue to determine which one is the
closest to the current city (from the first parameter) using the Euclidean distance
calculated in the next method (distBetweenCities). I must omit cities that already
marked in or out of the stack and the current city itself (otherwise a city will always be
the closest city to itself!). If the found city (with the smallest distance to current city) is
null, return null. Calculate the flight cost to this city and determine if it is affordable with
the band's current money. If so, return the city, but if it is not affordable then return null.

Without providing a complete solution, here are several pointers you might like to consider:

• You seem to be dequeuing and enqueuing for the purpose of viewing the head of the queue. If your CircularArrayQueue implements Queue it should have a peek method that views the head without removing it.
• The or operators in your filter condition should probably be and (&&) if I'm reading your requirements correctly
• As you mention, your logic is pretty flaky in findNextCity it kinda seems to look for the first city that is smaller than the distance to the next city or something like that

You probably need something like:

City closestCity = null;
for (City testCity: cityQueue) {
if (testCity != currCity 
&& !testCity.isMarkedInStack() && !testCity.isMarkedOutOfStack()
&& (closestCity == null || distance(currCity, closestCity) > distance(currCity, testCity))
closestCity == testCity;
}