代码实现
package arrayQueue;
import java.util.Scanner;
public class CircleArrayQueue {
public static void main(String[] args) {
CircleQueue queue = new CircleQueue(4);
char key = ' '; // 接受用户输入字符
boolean flag = true;
Scanner sc = new Scanner(System.in);
while (flag) {
System.out.println("s: 显示队列");
System.out.println("e: 退出程序");
System.out.println("a: 添加元素");
System.out.println("g: 元素出队列");
System.out.println("h: 查看头元素");
key = sc.next().charAt(0);
switch (key) {
case 's':
queue.showQueue();
break;
case 'a':
System.out.println("请输入一个数");
int val = sc.nextInt();
queue.add(val);
break;
case 'g':
try {
int res = queue.get();
System.out.printf("取出的数据是%d", res);
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 'h':
try {
int res = queue.showHead();
System.out.printf("取出的数据是%d", res);
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 'e':
sc.close();
flag = false;
break;
default:
break;
}
}
System.out.println("程序退出");
}
}
class CircleQueue {
private int rear; // 为了预留一个空间，指向队列最后一个元素的后一个位置
private int front; // 指向队列的第一个元素的位置
private int maxSize;
private int[] arr;
public CircleQueue(int arrayMaxSize) {
maxSize = arrayMaxSize;
rear = 0; // 尾指针，指向队列最后一个元素的后一个位置
front = 0; // 头指针，指向队列第一个元素的位置
arr = new int[maxSize];
}
public boolean isFull() {
return (rear + 1 + maxSize - front) % maxSize == 0;
}
public boolean isEmpty() {
return rear == front;
}
// 队列添加元素
public void add(int value) {
if (isFull()) {
System.out.println("队列满，无法添加");
return;
}
arr[rear] = value;
rear = (rear + 1) % maxSize;
}
// 队列取数据
public int get() {
if (isEmpty()) {
throw new RuntimeException("队列为空");
}
int value = arr[front];
front = (front + 1) % maxSize;
return value;
}
// 展示队列所有数据
public void showQueue() {
if (isEmpty()) {
System.out.println("队列为空，没有数据");
return;
}
for (int i = front; i < front + size(); i++) {
System.out.printf("arr[%d]=%d\n", i % maxSize, arr[i % maxSize]); // 注意这里两个值的计算
}
}
private int size() {
return (rear + maxSize - front) % maxSize;
}
// 展示队列头数据
public int showHead() {
if (isEmpty()) {
throw new RuntimeException("队列为空");
}
return arr[front];
}
}
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