队列

class Queue():
    def __init__(self):
        self.__items=[]
    def is_empty(self):
        return self.__items==[]
    def length(self):
        return len(self.__items)
    def travel(self):
        if self.is_empty():
            return False
        for i in self.__items:
            print(i,end='')
        print('')
    def add(self,item):
        self.__items.append(item)
    def pop(self):
        self.__items.pop(0)
if __name__ == '__main__':
    qq=Queue()
    for i in range(10):
        qq.add(i)
    qq.travel()
    print(qq.length())
    qq.add(1)
    qq.travel()
    qq.pop()
    qq.travel()