//循環(huán)隊(duì)列
class CirQueue{
 private int QueueSize;
 private int front;
 private int rear;
 private int[] queueList ;
 
 public CirQueue(int QueueSize){
  this.QueueSize = QueueSize; 
  queueList = new int[QueueSize];
  front = 0;
  rear = 0;
 }
 
 //獲取隊(duì)列頭元素
 public int getQueueElement(){
  //如果隊(duì)列不為空，返回隊(duì)頭元素，否則拋出異常提示隊(duì)列為空
  int element = -1;
  if(!isEmpty()){
   element = queueList[front];
   return element;
  }
  else {
   System.out.println("隊(duì)列為空");
   return -1;
  }
  
 }
 
 //出隊(duì)
 public int deQueue(){
  int element = -1;
  if(!isEmpty()){
   element = queueList[front];
   front =(front+1)%QueueSize;
   return element;
  }
  else {
   System.out.println("隊(duì)列為空");
   return -1;
  }
  
 }
 
 
 
 
 
 //入隊(duì)
 public void enQueue(int element){
  //如果隊(duì)列未滿，添加元素到隊(duì)尾，否則提示隊(duì)列已滿
  if(!isFull()){
   queueList[rear] = element ;
   rear = (rear+1)%QueueSize;
   
  }
  else {
   System.out.println("隊(duì)列已滿");
  }
 }
 
 //判斷隊(duì)列是否為空
 public boolean isEmpty(){
  boolean b = false;
  if(rear == front)
   b = true;
  return b;
 }
 
 
 //判斷隊(duì)列是否已滿
 public boolean isFull(){
  boolean b = false;
  if((rear+1)%QueueSize == front)
   b = true;
  return b;
 }

}

package com.test;

import java.util.*;


public class StructTest {

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  
  //新建并初始化存儲(chǔ)空間為3的循環(huán)隊(duì)列（方便判斷隊(duì)滿條件，浪費(fèi)一個(gè)數(shù)組空間）
  CirQueue cirQueue = new CirQueue(4);
  //入隊(duì)3個(gè)元素
  cirQueue.enQueue(1);
  cirQueue.enQueue(2);
  cirQueue.enQueue(3);
  
  //獲取隊(duì)頭元素,獲取 但不改變隊(duì)列
  int temp = cirQueue.getQueueElement();
  System.out.println(temp);
  
  //出隊(duì) 獲取隊(duì)頭元素，并且隊(duì)頭指針往后移一位
  temp = cirQueue.deQueue();
  System.out.println(temp);
  
  //再次獲取隊(duì)頭元素
  temp = cirQueue.getQueueElement();
  System.out.println(temp);
  
  
 }

}

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