队列的实现

class Queue():
    def __init__(self, size=100):
        self.rear = 0
        self.front = 0
        self.size = size + 1
        self.li = [0 for _ in range(self.size)]

    def is_empty(self):
        return self.front == self.rear

    def is_full(self):
        return (self.rear + 1) % self.size == self.front

    def en_queue(self, element):
        if not self.is_full():
            self.rear = (self.rear + 1) % self.size
            self.li[self.rear] = element
        else:
            raise IndexError("The queue is filled!")

    def de_queue(self):
        if not self.is_empty():
            self.front = (self.front + 1) % self.size
            return self.li[self.front]
        else:
            raise IndexError("The queue is empty!")


if __name__ == '__main__':
    que = Queue(5)
    for i in range(3):
        que.en_queue(i)
    for _ in range(2):
        print(que.de_queue())
    for i in range(3, 7):
        que.en_queue(i)
    for _ in range(5):
        print(que.de_queue())