package DataStructure;
 
/**
 * Created by Hubbert on 2017/11/11.
 */
public class Queue {
 
  private int [] arr ;
  private int front ; //隊(duì)頭指針
  private int rear ; //隊(duì)尾指針
  private int nItems ;//隊(duì)列中的個(gè)數(shù)
  private int maxSize;//隊(duì)列長(zhǎng)度
 
  //使用構(gòu)造函數(shù)進(jìn)行初始化
  public Queue( int maxSize ){
    this.maxSize = maxSize ;
    this.arr = new int [this.maxSize];
    this.nItems = 0 ;
    this.front = 0;
    this.rear = -1 ;
  }
 
  public boolean isFull(){
    return (nItems == maxSize);//判斷隊(duì)列是否已滿
  }
 
  public boolean isEmpty(){
    return (nItems == 0);//判斷隊(duì)列是否為空
  }
 
  //插入
  public void insert( int number ){
    if(!isFull()){
      //處理循環(huán)隊(duì)列
      if( rear == (maxSize -1)){
        rear = -1;
      }
      arr[++rear] = number ;
      nItems++;
    }else{
      System.out.println("The Queue is full!!");
    }
  }
 
  //刪除
  public int remove(){
    if(!isEmpty()){
      //處理循環(huán)隊(duì)列
      if( front == maxSize ){
        front = 0;
      }
      nItems--;
      return arr[front++];
 
    } else {
      System.err.println ("The Queue is Empty!!");
      return -1;
    }
  }
 
  public static void main(String [] args){
    Queue queue = new Queue(5);
    queue.insert(22);
    queue.insert(33);
    queue.insert(44);
    queue.insert(55);
    queue.insert(66);
 
    System.out.println("-----------先刪除隊(duì)列中前兩個(gè)數(shù)據(jù)------------");
    System.out.println("Front--->Rear:");
    for( int i =0 ; i < 2 ; i++ ){
      System.out.print(queue.remove() + " ");
    }
 
    System.out.println("");
    System.out.println("-----------繼續(xù)使用隊(duì)列------------");
    System.out.println("Front--->Rear:");
    queue.insert(1);
    queue.insert(2);
    while (!queue.isEmpty()){
      System.out.print(queue.remove() + " ");
    }
  }
}