練習-循環キュー1

1.現在のキューから値を取るにつれて、最終的にはキューが同時に空と判断する、満と判断する場合がある.現在のキューは再利用できません.

public class ArrayQueueDemo {
     

    public static void main(String[] args) {
     
        ArrayQueue arrayQueue = new ArrayQueue(3);
        char key = ' ';
        boolean loop = true;
        Scanner scanner = new Scanner(System.in);
        while (loop) {
     
            System.out.println("s(show):    ");
            System.out.println("a(add):    ");
            System.out.println("g(get):    ");
            System.out.println("h(head):    ");
            key = scanner.next().charAt(0);
            switch (key) {
     
                case 's':
                    arrayQueue.showQueue();
                    break;
                case 'a':
                    System.out.println("     ");
                    int value = scanner.nextInt();
                    arrayQueue.addQueue(value);
                    break;

                case 'g':
                    try {
     
                        int res = arrayQueue.getQueue();
                        System.out.printf("      %d
", res);
                    } catch (Exception e) {
     
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'h':
                    try {
     
                        int res = arrayQueue.headQueue();
                        System.out.printf("      %d
", res);
                    } catch (Exception e) {
     
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'e':
                    loop = false;
                    break;
                default:
                    break;
            }
        }
        System.out.println("    ");
    }
}

class ArrayQueue {
     
    private int maxSize;
    private int front;
    private int rear;
    private int[] arr;

    public ArrayQueue(int arrMaxSize) {
     
        maxSize = arrMaxSize;
        arr = new int[maxSize];
        front = -1;//      。   front            
        rear = -1;//     ，        （           ）
    }

    public boolean isFull() {
     
        return rear == maxSize - 1;
    }

    public boolean isEmpty() {
     
        return rear == front;
    }

    public void addQueue(int n) {
     
        if (isFull()) {
     
            System.out.println("   ，      ");
            return;
        }
        rear++;
        arr[rear] = n;
    }

    public int getQueue() {
     
        if (isEmpty()) {
     
            throw new RuntimeException("    ,     ");
        }
        front++;
        return arr[front];
    }

    public void showQueue() {
     
        if (isEmpty()) {
     
            System.out.println("    ，    ");
            return;
        }
        for (int i = 0; i < arr.length; i++) {
     
            System.out.printf("arr[%d]=%d
", i, arr[i]);
        }
    }

    public int headQueue() {
     
        if (isEmpty()) {
     
            throw new RuntimeException("    ，    ");
        }
        return arr[front + 1];
    }
}