import java.util.Scanner;
/**
* 数组实现环形队列
*/
public class CircleArrayQueue2 {
public static void main(String[] args) {
System.out.println("测试数组模拟环形队列的案例~~~");
// 创建一个环形队列
CircleArray2 queue = new CircleArray2(4); //说明设置4
char key = ' '; // 接收用户输入
Scanner scanner = new Scanner(System.in);//
boolean loop = true;
// 输出一个菜单
while (loop) {
System.out.println("s(show): 显示队列");
System.out.println("e(exit): 退出程序");
System.out.println("a(add): 添加数据到队列");
System.out.println("g(get): 从队列取出数据");
System.out.println("h(head): 查看队列头的数据");
key = scanner.next().charAt(0);// 接收一个字符
switch (key) {
case 's':
queue.showQueue();
break;
case 'a':
System.out.println("输入一个数:");
int value = scanner.nextInt();
queue.addQueue(value);
break;
case 'g': // 取出数据
try {
int res = queue.getQueue();
System.out.printf("取出的数据是%d\n", res);
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.getMessage());
}
break;
case 'h': // 查看队列头的数据
try {
int res = queue.headQueue();
System.out.printf("队列头的数据是%d\n", res);
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.getMessage());
}
break;
case 'e': // 退出
scanner.close();
loop = false;
break;
default:
break;
}
}
System.out.println("程序退出~~");
}
}
class CircleArray2{
private int size = 0;//定义一个数据表示数组里有效的数据数量
private final int maxSize;//表示数组的最大容量
private int front=0; //指向数组的第一个元素的下标
private int rear=-1; //指向数组的最后一个元素的下标,初始值赋值为-1
private int[] arr;
public CircleArray2(int arrMaxSize) {
this.maxSize = arrMaxSize;
arr = new int[maxSize];
}
//判断队列是否满
public boolean isFull(){
return size==maxSize;
}
//判断对列是否为空
public boolean isEmpty(){
return size==0;
}
//添加数据到队列
public void addQueue(int data){
if (isFull()){
System.out.println("队列满,不能添加数据!");
return;
}
if (rear==(maxSize-1)){
rear=-1;
}
arr[rear+1] = data;
size++;
//添加数据后,rear向后移一位
rear++;
System.out.println("rear: "+rear);
}
//从队列中取出数据
public int getQueue(){
if (isEmpty()){
throw new RuntimeException("队列为空,不能取出数据!,请添加数据!");
}
int value=arr[front];
size--;
front = (front +1)%maxSize;
return value;
}
//显示所有数据
public void showQueue(){
// 判断
if (isEmpty()) {
System.out.println("队列为空!没有数据!");
return;
}
if(front<=rear){
for (int i = front; i <=rear ; i++) {
System.out.printf("arr[%d]=%d\n", i , arr[i]);
}
}
if (front>rear){
for (int i = front; i <maxSize ; i++) {
System.out.printf("arr[%d]=%d\n", i , arr[i]);
}
for (int i = 0; i <=rear ; i++) {
System.out.printf("arr[%d]=%d\n", i , arr[i]);
}
}
System.out.println();
}
//获取对列头数据
public int headQueue() {
// 判断
if (isEmpty()) {
throw new RuntimeException("队列空的,没有数据~~");
}
return arr[front];
}
}
来源:oschina
链接:https://my.oschina.net/u/4707974/blog/4720817