数据结构--队列--范例

“  每天都可以成长一点点”

01

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public class ArrayQueue {
//队列容量
public int size;
//队列头部下标
public int front;
//队列尾部下标
public int rear;
//数组
public int arr[];

public ArrayQueue(int size){
this.size = size + 1; //默认留一个空地址
this.front = 0;
this.rear = 0;
this.arr = new int[size+1];
    }

/**
     * 是否满队
* @return
     */
public boolean isFull(){
return (rear+1) % size == front;
    }

/**
     * 是否空队
* @return
     */
public boolean isEmpty(){
return rear == front;
    }

/**
     * 入队
* @param item
*/
public void push(int item){
if(isFull()){
throw new RuntimeException("队列已满，入队失败");
        }
arr[rear] = item;
rear = (rear + 1) % size;
    }

/**
     * 出队
* @return
     */
public int pop(){
if(isEmpty()){
throw new RuntimeException("队列为空");
        }
int item = arr[front];
front = (front + 1) % size;
return item;
    }

/**
     * 队列长度
* @return
     */
public int length(){
return (rear + size - front) % size;
    }

/**
     * 显示整个队列
*/
public void show(){
if(isEmpty()){
throw new RuntimeException("队列为空");
        }
for (int i = front; i < front+length(); i++) {
System.out.print(arr[i%size]+"\t");
        }
System.out.printf("\n");
    }

public int getHeader(){
if(isEmpty()){
throw new RuntimeException("队列为空");
        }
return arr[front];
    }
}