使用 toString 打印循环队列
using toString to print Circular Queue
我正在尝试寻找一种更简单的方法来打印圆形阵列队列。这是我目前所拥有的。
public class CircularArrayQueue<T> implements QueueADT<T>
{
private final static int DEFAULT_CAPACITY = 100;
protected int front, rear, count;
private T[] queue;
/**
* Creates an empty queue using the specified capacity.
* @param initialCapacity the initial size of the circular array queue
*/
public CircularArrayQueue (int initialCapacity)
{
front = rear = 0;
count = 0;
queue = (T[]) (new Object[initialCapacity]);
}
/**
* Creates an empty queue using the default capacity.
*/
public CircularArrayQueue()
{
this(DEFAULT_CAPACITY);
}
/**
* Adds the specified element to the rear of this queue, expanding
* the capacity of the queue array if necessary.
* @param element the element to add to the rear of the queue
*/
public void enqueue(T element)
{
if (size() == queue.length)
expandCapacity();
//assign element to the queue
queue[rear] = element;
//update the rear of queue
rear = (rear+1) % queue.length;
count++;
}
/**
* Removes the element at the front of this queue and returns a
* reference to it.
* @return the element removed from the front of the queue
* @throws EmptyCollectionException if the queue is empty
*/
public T dequeue() throws EmptyCollectionException
{
if (isEmpty())
throw new EmptyCollectionException("queue");
//remove from front of the queue
T result = queue[front];
queue[front] = null;
//update the front of the queue
front = (front+1) % queue.length;
//update the queue size
count--;
return result;
}
/**
* Creates a new array to store the contents of this queue with
* twice the capacity of the old one.
*/
private void expandCapacity()
{
T[] larger = (T[]) (new Object[queue.length *2]);
for (int scan = 0; scan < count; scan++)
{
larger[scan] = queue[front];
front = (front + 1) % queue.length;
}
front = 0;
rear = count;
queue = larger;
}
/**
* Returns true if this queue is empty and false otherwise.
* @return true if this queue is empty
*/
public boolean isEmpty()
{
return count == 0;
}
/**
* Returns the number of elements currently in this queue.
* @return the size of the queue
*/
public int size()
{
return count;
}
/**
* Returns a string representation of this queue.
* @return the string representation of the queue
*/
public String toString()
{
String temp = "";
if(isEmpty())
System.out.println("\nCircular Queue is Empty!!!\n");
else{
for(int i = front; i < queue.length; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
for(int i = 0; i < rear; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
//This seems like it would work if the front != rear
/* for(int i = front; i != rear; i = (i + 1) % queue.length){
temp += "queue[" + i + "] = " + queue[i] + "\n";
System.out.println("queue[" + i + "] = " + queue[i] + "\n");
}*/
}
return temp;
}
}
这是我的主要内容：
public static void main(String[] args) throws EmptyCollectionException
{
CircularArrayQueue<Integer> arrayQueue = new CircularArrayQueue<>(5);
//Add to the queue
arrayQueue.enqueue(1);
arrayQueue.enqueue(2);
arrayQueue.enqueue(3);
arrayQueue.enqueue(4);
arrayQueue.enqueue(5);
//Print info about the queue
System.out.println("\n***");
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
//Removes two elements from the front of the queue
arrayQueue.dequeue();
arrayQueue.dequeue();
//Displays the info after removing two elements from the queue
System.out.println("AFTER DQ");
System.out.println("\n***");
//Print info about the queue
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
//Adds two elements to the back of the queue.
arrayQueue.enqueue(6);
arrayQueue.enqueue(7);
//Displays the info after adding two elements to the back of queue
System.out.println("AFTER ENQUEUE");
System.out.println("\n***");
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
}
输出：
***Zero index of the queue is the front to start***
//After placing 5 elements in the queue the front and rear are the same.
//So if we were to add another element to the rear it would override the
//index 0 and then rear would get updated to index 1(if we didn't expand the array).
count = 5
front = 0
rear = 0
queue[0]=1
queue[1]=2
queue[2]=3
queue[3]=4
queue[4]=5
//After removing 2 elements from the front of the queue. The front value changes.
//The rear is still the same.
count = 3
front = 2
rear = 0
queue[2]=3
queue[3]=4
queue[4]=5
//After adding 2 more elements to the queue. The front and the rear are the same again and the queue is full.
count = 5
front = 2
rear = 2
queue[2]=3
queue[3]=4
queue[4]=5
queue[0]=6
queue[1]=7
所以基本上，如果你看一下我的 toString 方法，我使用了两个 for 循环来打印队列。
public String toString()
{
String temp = "";
if(isEmpty())
System.out.println("\nCircular Queue is Empty!!!\n");
else{
for(int i = front; i < queue.length; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
for(int i = 0; i < rear; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
}
return temp;
}
我尝试实现这个 toString 但当 front == rear 时它不起作用。
我希望只使用一个 for 循环来使这个方法 order(n).
public String toString(){
String temp = "";
//This seems like it would work if the front != rear
for(int i = front; i != rear; i = (i + 1) % queue.length){
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
return temp;
}
使用此 toString 的输出：
***Zero index of the queue is the front to start***
//After placing 5 elements in the queue the front and rear are the same.
//So if we were to add another element to the rear it would override the
//index 0 and then rear would get updated to index 1(if we didn't expand the array).
count = 5
front = 0
rear = 0
//After removing 2 elements from the front of the queue. The front value changes.
//The rear is still the same.
count = 3
front = 2
rear = 0
queue[2]=3
queue[3]=4
queue[4]=5
//After adding 2 more elements to the queue. The front and the rear are the same again and the queue is full.
count = 5
front = 2
rear = 2
如果有人能提出任何建议，那就太棒了。对不起，如果我没有解释清楚。
我会尝试这样的事情：
int i = 0;
while(i < size)
{
int index = (i + front) % size
if(queue[index] != null);
System.out.println("queue[" + index + "] = " + queue[index]);
i++;
}
int num = front;
for(int i = 0; i < count; i++){
temp += "CircularQueue[" + num + "] = " + queue[num] +"\n";
num = (num + 1) % queue.length;
}
这似乎对我有用。
我正在尝试寻找一种更简单的方法来打印圆形阵列队列。这是我目前所拥有的。
public class CircularArrayQueue<T> implements QueueADT<T>
{
private final static int DEFAULT_CAPACITY = 100;
protected int front, rear, count;
private T[] queue;
/**
* Creates an empty queue using the specified capacity.
* @param initialCapacity the initial size of the circular array queue
*/
public CircularArrayQueue (int initialCapacity)
{
front = rear = 0;
count = 0;
queue = (T[]) (new Object[initialCapacity]);
}
/**
* Creates an empty queue using the default capacity.
*/
public CircularArrayQueue()
{
this(DEFAULT_CAPACITY);
}
/**
* Adds the specified element to the rear of this queue, expanding
* the capacity of the queue array if necessary.
* @param element the element to add to the rear of the queue
*/
public void enqueue(T element)
{
if (size() == queue.length)
expandCapacity();
//assign element to the queue
queue[rear] = element;
//update the rear of queue
rear = (rear+1) % queue.length;
count++;
}
/**
* Removes the element at the front of this queue and returns a
* reference to it.
* @return the element removed from the front of the queue
* @throws EmptyCollectionException if the queue is empty
*/
public T dequeue() throws EmptyCollectionException
{
if (isEmpty())
throw new EmptyCollectionException("queue");
//remove from front of the queue
T result = queue[front];
queue[front] = null;
//update the front of the queue
front = (front+1) % queue.length;
//update the queue size
count--;
return result;
}
/**
* Creates a new array to store the contents of this queue with
* twice the capacity of the old one.
*/
private void expandCapacity()
{
T[] larger = (T[]) (new Object[queue.length *2]);
for (int scan = 0; scan < count; scan++)
{
larger[scan] = queue[front];
front = (front + 1) % queue.length;
}
front = 0;
rear = count;
queue = larger;
}
/**
* Returns true if this queue is empty and false otherwise.
* @return true if this queue is empty
*/
public boolean isEmpty()
{
return count == 0;
}
/**
* Returns the number of elements currently in this queue.
* @return the size of the queue
*/
public int size()
{
return count;
}
/**
* Returns a string representation of this queue.
* @return the string representation of the queue
*/
public String toString()
{
String temp = "";
if(isEmpty())
System.out.println("\nCircular Queue is Empty!!!\n");
else{
for(int i = front; i < queue.length; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
for(int i = 0; i < rear; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
//This seems like it would work if the front != rear
/* for(int i = front; i != rear; i = (i + 1) % queue.length){
temp += "queue[" + i + "] = " + queue[i] + "\n";
System.out.println("queue[" + i + "] = " + queue[i] + "\n");
}*/
}
return temp;
}
}
这是我的主要内容：
public static void main(String[] args) throws EmptyCollectionException
{
CircularArrayQueue<Integer> arrayQueue = new CircularArrayQueue<>(5);
//Add to the queue
arrayQueue.enqueue(1);
arrayQueue.enqueue(2);
arrayQueue.enqueue(3);
arrayQueue.enqueue(4);
arrayQueue.enqueue(5);
//Print info about the queue
System.out.println("\n***");
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
//Removes two elements from the front of the queue
arrayQueue.dequeue();
arrayQueue.dequeue();
//Displays the info after removing two elements from the queue
System.out.println("AFTER DQ");
System.out.println("\n***");
//Print info about the queue
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
//Adds two elements to the back of the queue.
arrayQueue.enqueue(6);
arrayQueue.enqueue(7);
//Displays the info after adding two elements to the back of queue
System.out.println("AFTER ENQUEUE");
System.out.println("\n***");
System.out.println("count = " + (arrayQueue.count));
System.out.println("front = " + (arrayQueue.front));
System.out.println("rear = " + arrayQueue.rear);
System.out.print(arrayQueue.toString());
System.out.println("***\n");
}
输出：
***Zero index of the queue is the front to start***
//After placing 5 elements in the queue the front and rear are the same.
//So if we were to add another element to the rear it would override the
//index 0 and then rear would get updated to index 1(if we didn't expand the array).
count = 5
front = 0
rear = 0
queue[0]=1
queue[1]=2
queue[2]=3
queue[3]=4
queue[4]=5
//After removing 2 elements from the front of the queue. The front value changes.
//The rear is still the same.
count = 3
front = 2
rear = 0
queue[2]=3
queue[3]=4
queue[4]=5
//After adding 2 more elements to the queue. The front and the rear are the same again and the queue is full.
count = 5
front = 2
rear = 2
queue[2]=3
queue[3]=4
queue[4]=5
queue[0]=6
queue[1]=7
所以基本上，如果你看一下我的 toString 方法，我使用了两个 for 循环来打印队列。
public String toString()
{
String temp = "";
if(isEmpty())
System.out.println("\nCircular Queue is Empty!!!\n");
else{
for(int i = front; i < queue.length; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
for(int i = 0; i < rear; i++){
if(queue[i] != null)
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
}
return temp;
}
我尝试实现这个 toString 但当 front == rear 时它不起作用。 我希望只使用一个 for 循环来使这个方法 order(n).
public String toString(){
String temp = "";
//This seems like it would work if the front != rear
for(int i = front; i != rear; i = (i + 1) % queue.length){
temp += "queue[" + i + "] = " + queue[i] + "\n";
}
return temp;
}
使用此 toString 的输出：
***Zero index of the queue is the front to start***
//After placing 5 elements in the queue the front and rear are the same.
//So if we were to add another element to the rear it would override the
//index 0 and then rear would get updated to index 1(if we didn't expand the array).
count = 5
front = 0
rear = 0
//After removing 2 elements from the front of the queue. The front value changes.
//The rear is still the same.
count = 3
front = 2
rear = 0
queue[2]=3
queue[3]=4
queue[4]=5
//After adding 2 more elements to the queue. The front and the rear are the same again and the queue is full.
count = 5
front = 2
rear = 2
如果有人能提出任何建议，那就太棒了。对不起，如果我没有解释清楚。
我会尝试这样的事情：
int i = 0;
while(i < size)
{
int index = (i + front) % size
if(queue[index] != null);
System.out.println("queue[" + index + "] = " + queue[index]);
i++;
}
int num = front;
for(int i = 0; i < count; i++){
temp += "CircularQueue[" + num + "] = " + queue[num] +"\n";
num = (num + 1) % queue.length;
}
这似乎对我有用。