public class sss {
    private final int[] queue;
    private int top;//指向最新进来的元素的下一个元素

    public sss(int size) {
        queue = new int[size];
        top = 0;
    }

    public void push(int item) throws Exception {//往队列中添加元素
        if (top > queue.length) {
            throw new Exception("QueueOverflowError");
        } else {
            queue[top] = item;
            top++;
        }
    }

    public int pop() throws Exception {//队列第一个元素出列
        if (top == 0) {
            throw new Exception("QueueEmpty");
        } else {
            int oldOne = queue[0];
            System.arraycopy(queue, 1, queue, 0, top);
            top--;
            return oldOne;
        }
    }

    public int peek() throws Exception {//查看队列的第一个元素
        if (top == 0) {
            throw new Exception("QueueEmpty");
        } else {
            return queue[0];
        }
    }

}