Ok so it was easy to implement a circular queue with an array.
Here I have code which tries to implement a circular queue using an arraylist. the problem is that even though i have implemented my deque and enque methods this does not work with my arraylist(however this works with a normal array)....
Unlike an array if i use this code on my arraylist it seems to be removing and adding wrongly at different positionns
import java.util.*;
public class People {
private final int DEFAULT_CAPACITY = 100;
private int front, rear, count;
private ArrayList<thePeople> people;
private int theMaxCapacity;
//-----------------------------------------------------------------
// Creates an empty queue using the specified capacity.
//-----------------------------------------------------------------
public People(int initialCapacity) {
front = rear = count = 0;
people = new ArrayList<thePeople>(Collections.nCopies(5, (thePeople) null));
}
//-----------------------------------------------------------------
// Adds the specified element to the rear of the queue, expanding
// the capacity of the queue array if necessary.
//-----------------------------------------------------------------
public void enque(thePeople element) {
if (this.isFull()) {
System.out.println("Queue Full");
System.exit(1);
} else {
people.set(rear, element);
rear = rear + 1;
if (rear == people.size()) {
rear = 0;
}
count++;
}
}
//-----------------------------------------------------------------
// Removes the element at the front of the queue and returns a
// reference to it. Throws an EmptyCollectionException if the
// queue is empty.
//-----------------------------------------------------------------
public thePeople dequeue() {
if (isEmpty()) {
System.out.println("Empty Queue");
}
thePeople result = people.get(front);
people.set(front, null);
front = (front + 1) % people.size();
count--;
return result;
}
//-----------------------------------------------------------------
// Returns true if this queue is empty and false otherwise.
//-----------------------------------------------------------------
public boolean isEmpty() {
return (count == 0);
}
//-----------------------------------------------------------------
// Returns the number of elements currently in this queue.
//-----------------------------------------------------------------
public int size() {
return count;
}
public boolean isFull() {
return count == people.size();
}
public void mySimulation() {
Random rand1 = new Random();
thePeople theM = null;
if (this.isFull()) {
this.people.remove(0);
System.out.println("Enqueueing...");
this.enque(people.get(rand1.nextInt(people.size())));
thePeople r1 = people.get(rear - 1);
System.out.println(people.toString());
System.out.println(r1);
for (int e = 0; e < people.size(); e++) {
if (people.get(e) instanceof thePeople) {
System.out.println("G");
} else {
System.out.println("D");
}
}
}
}
//-----------------------------------------------------------------
// Returns a string representation of this queue.
//-----------------------------------------------------------------
@Override
public String toString() {
String result = "";
int scan = 0;
while (scan < count) {
if (people.get(scan) != null) {
result += people.get(scan).toString() + "\n";
}
scan++;
}
return result;
}
public static void main(String[] args) {
People Q1 = new People(25);
thePeople call1 = new thePeople("John King", "001 456 789");
thePeople call2 = new thePeople("Michael Fish", "789 654 321");
Q1.enque(call1);
Q1.enque(call2);
System.out.println(Q1.toString());
ArrayList<thePeople> callerDetails = new ArrayList<>(Arrays.asList(call1, call2));
Random rand = new Random();
for (int z = 0; z <= 4; z++) {
Q1.enque(callerDetails.get(rand.nextInt(callerDetails.size())));
}
System.out.println(Q1.toString());
}
}
my question is that how can I modify the enque and deque methods to work with an araylist(a circular queue arraylist) ?
ArrayDeque.