環形佇列可以使用陣列實現，也可以使用迴圈連結串列實現。

package www.bittech;

public class MyCircularQueue {
    private int front;//佇列頭
    private int rear;//佇列尾
    private int usedSize;//資料個數
    private int[] elem;//陣列
    public MyCircularQueue(int k){
        this.elem=new int[k];
        this.front=0;
        this.rear=0;
        this.usedSize=0;
    }
    public boolean enQueue(int value){
        if(isFull()){
            return false;
        }
        this.elem[this.rear]=value;
        this.usedSize++;
        this.rear=(this.rear+1)%this.elem.length;
        return true;
    }
    //隊尾下標加上1在%
    public boolean isFull(){
        if((this.rear+1)%this.elem.length==this.front){
            return true;
        }
        return false;
    }
    public boolean isEmpty(){
        return this.rear==this.front;
    }
    public boolean deQueue(int value){
        if(isEmpty()){
            return false;
        }
        this.elem[front]=value;
        this.front=(this.front+1)%this.elem.length;
        this.usedSize--;
        return true;
    }
    public int Front(){
        if(isEmpty()){
            throw new UnsupportedOperationException("佇列為空");
        }
        return this.elem[this.front];
    }
     public int Rear(){
         if(isEmpty()){
             throw new UnsupportedOperationException("佇列為空");
         }
         int index=this.rear == 0 ? this.elem.length-1 : this.rear-1;
         return this.elem[index];
     }

}